Pool won't hold chlorine/visual etching starting

[Pogueld]

Hi Kat,

First things first...
:arrow: Regarding your current chlorine demand... I don't think anyone caught this from your very first post in this thread:


Yellow stuff is Sodium Bromide [emoji33]
I'm almost sure that's why your pool is eating chlorine like it is!
Maybe a mod can see if ChemGeek can revisit this thread...
I would hold off doing anything else except adding bleach, like you have been, until Richard can advise you further... Adding the Bromide definitely complicates things.

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As far as your CYA measurement goes... You need to test in the same way every time... It is the test that is the most problematic for most people because there isn't a color change threshold like we are used to. And it is so dependent on viewing conditions.
Look at this link:Why test CYA? to see how the test looks when viewed from above. Is that helpful?
Some tips I've learned:

• you should test in the daylight, with approximately the same intensity of bright sunlight every time.
• Stand with your back to the sun, and let your body shade the tube. But do not stand in the shade of a tree, etc. or on the porch.
• Hold tube at waist level so you can look directly into the tube.
• Add the test mixture a few drops at a time, until the dot begins to "fade" then slow to one drop at a time until finally the dot is no longer visible .
• If you're unsure when the dot disappears, pour the solution from the tube back into the test bottle and start over. You can do this as many times as you need to. (But don't obsess, )
• when you're satisfied that you're done,raise the tube up to eye level to view the scale on the side, and read the measurement.
• Round up to the next higher value... The scale is logarithmic, so midway between say, 50 & 60 is not 55. Just call it 60. Better safe than sorry, as they say.

For the CYA test, the key is consistency. It must be done under the same conditions each time in order to have reliable results. Even then, there's a pretty wide margin of error, I think it's +/- 20 or 30ppm...(probably to account for all the different ways people test).
So even if you try your best to do the test the same every single time, it's possible to have results that seem a little " off"... When actually there's nothing "wrong" at all.

That's where getting to know your pool is beneficial--- for example, you might think your CYA has gone down 10 ppm but your chlorine is holding, same as always, and all your other chemistry is fine. You decide to just watch and wait, and maintain everything just as you normally do, as if nothing has changed... Sure enough, a few weeks later, when you check the CYA again, your level has "magically" returned to the original number. Good thing you didn't panic and add more, or let your FC drop in response to one oddball reading.
I've found that it is very impoortant to keep good records, and practice patience... Don't make changes to CYA unless there is other evidence that backs up the unusual result. Otherwise, you will end up with wild test results, and never be able to keep up.

(btw: CYA reagent is pretty inexpensive on Amazon... I got a 16 oz bottle for under $10... And kept in a cool, dark place, it won't go bad for several years at least... Get some before you run out. And you may need more FAS-DPD reagent* while you're at it Both are also available from tftestkits.net, which is run by Dave S., the owner of troublefreepools.com)


Good luck.

Thank you for this April! This is a hard test!


[emoji176] Lisa P.
Sent from my iPhone using Tapatalk

 

[katwar]

AprilsZoo, thank you very much for all of this in depth information. I think I need to clarify a few things first though. I do already have a large bottle of the CYA reagent and have been testing my CYA fairly regularly for the past year that I have owned this pool. My first post was to state that my water was no longer holding chlorine, I had a CYA level over 100 and I had microscopic yellow dots all over the entire pool floor and wall evenly and consistently. I had shocked my pool as part of regular maintenance (was using pucks at the time) and my chlorine wouldn't hold. Even though the yellow wouldn't scrub off with a wire brush I added the Jacks Yellow Stuff for grins and giggles only to see if it might be some type of yellow algae.

BUT, since then, I have done a 60% drain and refill. Additionally, after the refill I have switched to liquid chlorine. I have no pucks in my chlorinator and it is set to off. My CYA was still 60 after the refill. For now I will have to live with that and will do periodic and gradual drain and refills going forward. And the yellow dots that I was seeing mysteriously disappeared with the pool drain. My new but boring white plaster was completely white and still fairly new looking with only very minor etching in a few places which I believe is normal after even only a year.

The evening that my pool was filled completely, I added almost two gallons of liquid bleach after entering my levels into the pool calculator on this site. The next morning my pool was crystal clear and blue (which it always has been). I then started testing the chlorine levels twice daily.

Each evening I have been having to add 1 gallon + of liquid bleach based on my daily chlorine levels. My morning levels are around 6 and by late afternoon they have fallen to anywhere from 1.5 to 2. This drop is requiring me to add at least another gallon each night. Last night was the fourth night I have had to add over a gallon. My only remaining question is, at what point should my need for so much chlorine go down? I understand the biggest benefit of using liquid is that it will keep my CYA levels down and remove the need for pucks as well as shock, assuming I can keep all of my levels normal. At almost $3 a gallon for the 8.25% bleach from Walmart, that is $90 a month at this rate. I didn't go through $90 in pucks and shock in an entire summer last year. And when I say "summer", I mean from April - October here in Houston. So I am trying to decide if adding 1 gallon daily will be my norm and if it is, I will have to rethink this method due to the extreme cost difference. I am hopeful however that someone can tell me that in another week or in a few days my chlorine requirements will go down. So that's really the only thing I'm waiting to hear back about, is the amount of chlorine need on a daily basis after a refill and for how long.

Kathy

Hi Kat,

First things first...
:arrow: Regarding your current chlorine demand... I don't think anyone caught this from your very first post in this thread:


Yellow stuff is Sodium Bromide 
I'm almost sure that's why your pool is eating chlorine like it is!
Maybe a mod can see if ChemGeek can revisit this thread...
I would hold off doing anything else except adding bleach, like you have been, until Richard can advise you further... Adding the Bromide definitely complicates things.

〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰〰
As far as your CYA measurement goes... You need to test in the same way every time... It is the test that is the most problematic for most people because there isn't a color change threshold like we are used to. And it is so dependent on viewing conditions.
Look at this link:Why test CYA? to see how the test looks when viewed from above. Is that helpful?
Some tips I've learned:

• you should test in the daylight, with approximately the same intensity of bright sunlight every time.
• Stand with your back to the sun, and let your body shade the tube. But do not stand in the shade of a tree, etc. or on the porch.
• Hold tube at waist level so you can look directly into the tube.
• Add the test mixture a few drops at a time, until the dot begins to "fade" then slow to one drop at a time until finally the dot is no longer visible .
• If you're unsure when the dot disappears, pour the solution from the tube back into the test bottle and start over. You can do this as many times as you need to. (But don't obsess, )
• when you're satisfied that you're done,raise the tube up to eye level to view the scale on the side, and read the measurement.
• Round up to the next higher value... The scale is logarithmic, so midway between say, 50 & 60 is not 55. Just call it 60. Better safe than sorry, as they say.

For the CYA test, the key is consistency. It must be done under the same conditions each time in order to have reliable results. Even then, there's a pretty wide margin of error, I think it's +/- 20 or 30ppm...(probably to account for all the different ways people test).
So even if you try your best to do the test the same every single time, it's possible to have results that seem a little " off"... When actually there's nothing "wrong" at all.

That's where getting to know your pool is beneficial--- for example, you might think your CYA has gone down 10 ppm but your chlorine is holding, same as always, and all your other chemistry is fine. You decide to just watch and wait, and maintain everything just as you normally do, as if nothing has changed... Sure enough, a few weeks later, when you check the CYA again, your level has "magically" returned to the original number. Good thing you didn't panic and add more, or let your FC drop in response to one oddball reading.
I've found that it is very impoortant to keep good records, and practice patience... Don't make changes to CYA unless there is other evidence that backs up the unusual result. Otherwise, you will end up with wild test results, and never be able to keep up.

(btw: CYA reagent is pretty inexpensive on Amazon... I got a 16 oz bottle for under $10... And kept in a cool, dark place, it won't go bad for several years at least... Get some before you run out. And you may need more FAS-DPD reagent* while you're at it Both are also available from tftestkits.net, which is run by Dave S., the owner of troublefreepools.com)


Good luck.

 

[katwar]

BKFamily1, I just saw this post from you after I replied to April just now. I think I understand what you're saying about the FC requirements being somewhat determined by the CYA levels. And the worse the CYA levels are, the more chlorine I will need to keep the FC levels at a normal and healthy level. And I do want a clear sparkling trouble free pool, and I have always had a clear pool, even when my CYA levels finally reached the point of nothing left for the chlorine to bond to. And I'm sure it was just a matter of time until it wasn't clear any longer. So I've got the "clear," just not the "trouble free" part yet...LOL. And "minimal cost" seems to be my greatest concern at this point. My last reply before this reply to you stated that using a gallon a night of liquid bleach will cost approximately $90 a month, which is more than I spend total on pucks and shock from April - October. When I bought the house last April, I bought a 50 lb bucket of shock and 50 lbs of pucks. I still have shock left from the first bucket and had just opened and started using my second bucket of pucks. So that's $200 for 7 months of pucks and shock vs $630 for 7 months of liquid chlorine. That's a HUGE difference. And even if I had to do a drain and refill once a year and factored in the cost of the water, it would still be a significant difference. NOW, with all of that said, I am hopeful that I will NOT have to continue using a gallon a day of liquid bleach and that over time my needs will be reduced, but so far no one has been able to tell me that. Since I had to quite my job two years ago to care for my mother with Alzheimers in my home, a SWG isn't an option right now. However, once I return to work I will seriously consider it because it sounds like a terrific choice. I truly love the principal of using the liquid bleach and keeping my CYA levels from jacking up again. And I am most hopeful that I can fully incorporate the TFP way of maintaining my pool because it's been wonderful having so many knowledgable folks helping me get through this and make the transition.

Kathy

A quick note for maintaining FC while away for days at a time - SWG is obviously a good option that would eliminate the use of pucks. Another thing to consider is a chemical addition pump to add liquid. Check out the Equipment section of the forums under Chemical Automation

In a previous post, you said "My Taylor K-2006 test kit manual shows the ideal chlorine level as 2.0 to 4.0 but someone said you want it as high as 9.0 when using liquid bleach." As has been mentioned, the Taylor recommendation is inadequate because it does not consider CYA level. To say you should always keep the FC at X is not accurate. To tell the complete story, one must say, for CYA of X, maintain FC at Y. More CYA means higher FC levels are required to maintain enough active chlorine to do the job. Refer to the CYA/Chlorine table for proper target and shock levels of FC based on your CYA level. And the target FC level is not "for liquid." It is a function of the CYA level, not a function of the source of chlorine. So whether you are using liquid or pucks, the target is the same. You just have to remember that if you are using pucks, you are adding CYA while you are adding FC, meaning your needed level of FC will continue to increase over time unless you are diluting by draining and refilling or through rain or some other means.

As far as having drained per PoolMath and still being high on CYA, remember that you thought you were at 110 but may have been higher since the test is inaccurate beyond 100.

Finally, trust me and stick with it. When I first got on TFP and started following the recommendations earlier this year, I was skeptical also. While the amounts of bleach you are adding may seem excessive, they are not. The first SLAM I did took around 50 gallons over a week! But if you stick with it, you will get the results you want - a clear sparkling trouble-free pool at minimal cost.

 

[bkfamily1]

Kathy,

I think what you are seeing is an increased cost due to an increased chlorine demand. I do not think the cost increase you are seeing is due (at least not entirely) to the cost of liquid versus pucks (trichlor). Check out this thread which discusses the cost of different sources of chlorine. You can plug in your own local prices for the pucks, liquid and other sources. I am sure you will not find that liquid costs 3 times as much as pucks.

Cost-Comparison-of-Chlorine-Sources

 

[katwar]

Well, it's only been four days of using liquid chlorine. All I know is that I am paying $2.96 for a gallon of Great Value 8.25% bleach at Walmart. And I am using 1+ gallon each day (actually the bottles are 121 oz). Figure the average month is 30 days. And $3 x 30 = $90 a month. I went back through my purchases for the shock and the pucks and when I compare, the liquid chlorine is indeed MUCH higher overall. BUT, like I said, I just wasn't sure if I will ALWAYS have to use a gallon a day or if I'm only using so much because of the refill. I saw in other threads that people said they used 5 cups a day or 7 cups a day, etc and I just kind of got it in my head that's likely what I can plan on using. But I know the size of the pool and other factors can determine the amount needed. Since no one has told me that my liquid chlorine requirements will go down gradually after the refill then I can only assume I will need to buy 30 gallons a month to maintain my chlorine levels. Is that a safe assumption? LOL.

,

Kathy,

I think what you are seeing is an increased cost due to an increased chlorine demand. I do not think the cost increase you are seeing is due (at least not entirely) to the cost of liquid versus pucks (trichlor). Check out this thread which discusses the cost of different sources of chlorine. You can plug in your own local prices for the pucks, liquid and other sources. I am sure you will not find that liquid costs 3 times as much as pucks.

Cost-Comparison-of-Chlorine-Sources

 

[bkfamily1]

Kathy,

I understand. At $2.94 for 121 oz of 8.25% bleach, you are at about $4.50 per pound of effective chlorine. I found 50 pound buckets of pucks at WalMart for $108 which is $2.36 per pound of effective chlorine which is about half. However, you can typically find liquid for less than what you are paying. For example, Target in your area has 8.25% in 121 oz bottles 4 for $8.94 which is $2.24 each bringing the effective chlorine cost to $3.41 per pound. If I watch, I can usually find 12.5% for $2 or $3 per gallon on sale. At that Target sale price, it is still almost 50% more costly in terms of chlorine content. However, there is also an added cost to the pucks of their downward affect on pH as detailed in that thread. Typically, trichlor is a bit more costly than liquid when this is considered. The specifics of costs in your area may vary, so liquid may not in fact be less costly. But it should be close if not less all things considered. And again, right now, you are using a lot of chlorine because of what is going on in your water, not because liquid is inherently more costly, at least not that much more if at all. And don't forget that you are in this situation at least in part because the pucks slowly but surely drove your CYA up until your effective chlorine level was inadequate leading to your current inability to maintain FC. So the extra cost you are incurring right now is a result of longer term puck use and the resultant upset of your chemistry which now requires extra chlorine and extra cost to get back under control.

 

[katwar]

So you think that maybe I’m using an exceptional amount of chlorine because of the CYA level of 60 then? I can’t believe I drained at least 70% of my water out and still have a CYA of 60…LOL. It really must have been significantly higher than 100 for sure. Like I said earlier, I wished I would have just drained the whole thing. AND….our temps have been in the upper 90’s the past couple of weeks and I know that the UV levels have got to be through the roof as well. Do you think if I can get my CYA levels down to around 40 by doing maybe 10% drain and refills that my chlorine requirements would also go down then? I think I got it in my head that I did a drain and refill and was starting with fresh water, so I couldn’t understand why I needed so much chlorine. But I now realize that with the stabilizer levels that remained in the water that didn’t get drained, the need for a higher amount of chlorine would still be there.

Okay, here’s my new plan. I’m going to try and drain about 10% of the water a couple of times a week for the next few weeks and see what kind of effect I can get on my CYA levels. I just don’t have the time or energy to do another huge drain right now with all of my other current responsibilities at home. I will continue using the liquid bleach in the interim and will do a complete re-assessment in a few weeks. I’m hopeful that if I can get the CYA level down some more that alone should help reduce the chlorine requirements. Although I imagine in a few weeks the UV levels here will be even worse.


And thank you for the information on the bleach at Target. That price difference will help a lot considering how much bleach I am going through.


And I would like to mention that ironically, my pH level for the past year has been so incredibly constant it’s not even funny. It’s always 7.6 no matter what. The only thing I never had to worry about so far thankfully.


Thank you so much for all of your time and efforts and helping me to better understand my situation, my options, and the explanation behind some of my frustrations regarding price and chlorine requirements. I truly appreciate the wonderful help from everyone involved in this thread!


Kathy

Kathy,

I understand. At $2.94 for 121 oz of 8.25% bleach, you are at about $4.50 per pound of effective chlorine. I found 50 pound buckets of pucks at WalMart for $108 which is $2.36 per pound of effective chlorine which is about half. However, you can typically find liquid for less than what you are paying. For example, Target in your area has 8.25% in 121 oz bottles 4 for $8.94 which is $2.24 each bringing the effective chlorine cost to $3.41 per pound. If I watch, I can usually find 12.5% for $2 or $3 per gallon on sale. At that Target sale price, it is still almost 50% more costly in terms of chlorine content. However, there is also an added cost to the pucks of their downward affect on pH as detailed in that thread. Typically, trichlor is a bit more costly than liquid when this is considered. The specifics of costs in your area may vary, so liquid may not in fact be less costly. But it should be close if not less all things considered. And again, right now, you are using a lot of chlorine because of what is going on in your water, not because liquid is inherently more costly, at least not that much more if at all. And don't forget that you are in this situation at least in part because the pucks slowly but surely drove your CYA up until your effective chlorine level was inadequate leading to your current inability to maintain FC. So the extra cost you are incurring right now is a result of longer term puck use and the resultant upset of your chemistry which now requires extra chlorine and extra cost to get back under control.

 

[bkfamily1]

Kathy,

Hang in there. I know it is frustrating. This is my first summer on TFP also, and it was tough at the beginning. You keep pouring crazy amounts of bleach in the pool, and it just seems to go on and on. But I am a true believer now, and my pool is better than it ever has been.

I am not saying your chlorine use is high because of the current 60 CYA. I am saying that your previous 100+ CYA, slowly accumulated through the use of trichlor pucks, got you to a point that so much FC was tied up by the CYA that there was not enough active FC left to stop the algae. And now that the algae has gotten a hold, it is taking a lot of chlorine (and time and testing and frustration) to stop it and kill it. And you had to drain a bunch of the water to get the CYA down to a manageable (if still somewhat high) CYA level to even start to make progress.

Given your location, if you get long hours of intense sunlight, having your CYA at 60 may not be a bad idea. I will leave it to others with more experience to comment about that. However, as I understand it, higher CYA does not mean higher chlorine usage. It means you have to maintain a higher level, but once you are at that level, I think the amount needed to maintain it is related to organics in the water and sunlight (the affect of which is less with higher CYA levels). I think the real issue with extremely high CYA like you had before you drained is that it takes very very high levels of FC to provide enough ective FC after what the CYA ties up to fight the active algae. So instead of adding a couple gallons to take the FC from 5 to 16 for a SLAM, you have to add 3 or 4 times as much or more to get to a very high FC to SLAM. And if your CYA is well past 100, you don't really know where it is, and don't really know if your FC is high enough or not.

You are making progress, though. Before, you could not get the FC to hold at all. Now I believe you got to 6 or so. Now that the CYA is down to 60, get your FC up to 24 or so (SLAM level for CYA of 60 from Chlorine CYA table) and keep it there. Follow the rest of the instructions for the SLAM (keep testing, adding chlorine as needed and brushing). Backwash the filter and vacuum debris as needed. Check OCLT each night. You will eventually see the OCLT come down and eventually get below 1. If the OCLT goes up, it means the organics are gaining ground on you, probably because the FC level is not being kept high enough for your CYA level. I will also add that it is important to look for and address areas like light niches, the underside of ladders and such that can hide big patches of algae with biofilms over them that stop the chlorine from killing them until they are brushed and cleaned.

Not sure what to think of the pH stability with the trichlor use. Maybe it is because you had new plaster installed last year? I think plaster affects pH when it is new. Hopefully someone can comment.

Finally, having said all that, someone commented earlier that the "Jack's yellow stuff" is sodium bromide, and they hinted that this can be an issue. But since then, nobody has mentioned it again or explained. Can someone explain? Is there something different or unusual about sodium bromide that could be part of Kathy's challenge?

 

[katwar]

You mentioned algae. Not sure if you mean that my pool likely had algae due to no chlorine holding or what exactly. I physically saw no green or any colors of any type of algae. It had only been three days between having a normal chlorine reading and having a zero reading with shock not helping. So not sure if three days is enough for algae to form or not.

It sounds like I do need to SLAM then? I couldn't get an answer on that either. The first night after the fill I added two gallons per the calculator. But it sounds like I need to go back and read the chlorine/CYA page and actually do a SLAM. Oh gosh, if I'm using 1-2 gallons a day in a non SLAM stage I can't even imagine how many gallons I would have to use to reach a SLAM level and maintain a SLAM level. And how long would I need to keep the pool at SLAM levels and what does doing that do exactly? As I said before, my water has always been crystal clear. And it was clear again the next morning after the fill and after adding two gallons of bleach. So I've never seen any visible signs of algae or had any problems with water that wasn't always clear.

QUOTE=bkfamily1;880877]Kathy,

Hang in there. I know it is frustrating. This is my first summer on TFP also, and it was tough at the beginning. You keep pouring crazy amounts of bleach in the pool, and it just seems to go on and on. But I am a true believer now, and my pool is better than it ever has been.

I am not saying your chlorine use is high because of the current 60 CYA. I am saying that your previous 100+ CYA, slowly accumulated through the use of trichlor pucks, got you to a point that so much FC was tied up by the CYA that there was not enough active FC left to stop the algae. And now that the algae has gotten a hold, it is taking a lot of chlorine (and time and testing and frustration) to stop it and kill it. And you had to drain a bunch of the water to get the CYA down to a manageable (if still somewhat high) CYA level to even start to make progress.

Given your location, if you get long hours of intense sunlight, having your CYA at 60 may not be a bad idea. I will leave it to others with more experience to comment about that. However, as I understand it, higher CYA does not mean higher chlorine usage. It means you have to maintain a higher level, but once you are at that level, I think the amount needed to maintain it is related to organics in the water and sunlight (the affect of which is less with higher CYA levels). I think the real issue with extremely high CYA like you had before you drained is that it takes very very high levels of FC to provide enough ective FC after what the CYA ties up to fight the active algae. So instead of adding a couple gallons to take the FC from 5 to 16 for a SLAM, you have to add 3 or 4 times as much or more to get to a very high FC to SLAM. And if your CYA is well past 100, you don't really know where it is, and don't really know if your FC is high enough or not.

You are making progress, though. Before, you could not get the FC to hold at all. Now I believe you got to 6 or so. Now that the CYA is down to 60, get your FC up to 24 or so (SLAM level for CYA of 60 from Chlorine CYA table) and keep it there. Follow the rest of the instructions for the SLAM (keep testing, adding chlorine as needed and brushing). Backwash the filter and vacuum debris as needed. Check OCLT each night. You will eventually see the OCLT come down and eventually get below 1. If the OCLT goes up, it means the organics are gaining ground on you, probably because the FC level is not being kept high enough for your CYA level. I will also add that it is important to look for and address areas like light niches, the underside of ladders and such that can hide big patches of algae with biofilms over them that stop the chlorine from killing them until they are brushed and cleaned.

Not sure what to think of the pH stability with the trichlor use. Maybe it is because you had new plaster installed last year? I think plaster affects pH when it is new. Hopefully someone can comment.

Finally, having said all that, someone commented earlier that the "Jack's yellow stuff" is sodium bromide, and they hinted that this can be an issue. But since then, nobody has mentioned it again or explained. Can someone explain? Is there something different or unusual about sodium bromide that could be part of Kathy's challenge?[/QUOTE]

 

[AprilsZoo]

Hi Kat,
Thanks for the clarification...��

I've been following your thread since the beginning and know that you are frustrated...

Even with the huge water exchange, bromide in a pool will (from everything I've read) cause chlorine use to go up by quite a bit for a while and then it will level off....
I pretty new to giving advice on this forum but I've been reading (lurking) for years here and at an older, similar site.
So I will defer to others who know about the chemistry complications that bromide introduces.


Anyway, you had mentioned that your CYA test showed increased #s when you hadn't added anything with stabilizer, and I was just trying to help you understand why your values might seem to change, even if they really haven't... The margin of error in that test is HUGE! If you don't do it exactly the same every time, and understand why it might seem off, it will get really frustrating, really fast... And you don't need any more frustration...

And funny, I ordered the extra large CYA reagent almost immediately after I got my k2006. And I love my testkit... The tf100 is a lot cheaper if you consider the per-use-cost, but I've been spoiled by my color-coded bottles in the k2006.

As to the cost of bleach, have you looked into getting 12-12.5% liquid chlorine from your pool store?

Walmart carries liquid chlorine, 10%, but I've not looked to see if it's cheaper or not, than their bleach... I suspect it's not, because people would be recommending it otherwise. If you look into it, make sure you compare it based on equiv. amounts--- the LQ comes in gallons, but last time I looked the great value bleach was 3.x quarts....

I am gonna try to pm Richard (ChemGeek) to get him to look at this again.


And for what it's worth, I think your water did have algae, giving it a barely there yellow color, that you noticed on the plaster points, because of the way light refracts through the water.
Now you are staving off the algae's full return with all the chlorine, but you aren't able to eradicate it, and that's partly why your pool is demanding so much chlorine right now. I still think the bromide may also figure into the chlorine appetite though.

 

[bkfamily1]

Kathy,

As I have heard Dave (duraleigh) say on a few occasions to great effect, let's go back to basics. [Dave, if I use your quote and explain anything wrongly, please correct me] Chlorine is only consumed by two things - organics and sunlight. The best way to know if you have organics is the OCLT (overnight chlorine loss test) which is detailed in the "How To" section of "Pool School" here on the forum. This tests the loss of chlorine at night when sunlight is taken out of the picture. So any loss is organics. In essence, you test your FC at night after dark. You test it again early in the morning before it is light out. Raed the How To for all the details. Any loss of FC during that time is due to organics in the water or in or on the surfaces of the pool and associated equipment (ladders, filters, lights, etc). The OCLT is the test that tells you when a SLAM is done since an OCLT of less than 1ppm means the organics are gone for all intents and purposes. It is also the way to know if you have organics in the water/pool, and if you do, then the way to get rid of them is to SLAM. Note that you can have pristine water and still have organics. I said "algae" earlier, but I was generalizing. It would have been more proper for me to say "organics" perhaps. Also note that there are pretty much always some organics in the pool that the FC is breaking down. Even if you do not have algae, there is sweat, suntan lotion, spit, leaves, bugs, etc. But when the chemistry is right, the rate of organic addition to the pool is below the amount that the chlorine being added can break down. So the FC stays where you want it. But if algae gets going, it can reproduce and spread faster than the chlorine can kill it. So if your CYA was high, and the FC was too low for the CYA level you had, then there was not enough active FC available to fight the organics including algae. The same thing can happen if all your chemistry is fine, and you have a big pool party, or a bunch of little kids peeing in your pool, or a heavy rainstorm wash a bunch of dirt or mulch from recent landscaping into the pool, or any one of a myriad of events that hits the pool with a heavy load that gets ahead of the chlorine. If that balance tips to the favor of the algae no matter how it happens, it gets going and quickly gets away from you, even if you do not see visible growth on the pool surfaces. Seeing an OCLT over 1 is the clear indicator that this has indeed happened. At that point, you have to raise the FC to a SLAM level to get back ahead of the algae and other organics to stop the growth, kill them and reverse course. As you get out in front of the algae and other organics, they will start being broken down and decresing in number. Then the rate with which they are consuming chlorine will go down. That will be seen as your OCLT results get lower and lower. Eventually, when they are gone, the OCLT will be less than 1, and the SLAM is done.

If you are starting at 5ppm FC, based on your 23K gallon pool, you will need to add a little over 5 gallons to get to the 24ppm FC SLAM level. After that, you just have to keep testing and adding to keep it there until you pass an OCLT. Read over the SLAM process in the How To section of the forum for complete details. Yes, it is a lot. But it will eventually kill off whatever is growing in the pool, and the consumption will drop to normal. And your pool will be clean and stay that way as long as you maintain the chemistry from there,

By the way, I meant to tell you I found that Target special at this site. http://poncatechsquad.com/Dan/Chlorine/ I am not sure who, but it was done by another TFP member I believe. Nice tool.

 

[katwar]

The bromide source being the Jacks Yellow stuff you mean?

 

[katwar]

More great info. Wow, my head is spinning with all of this wonderful knowledge sharing. Not sure if this will matter or not but I'll throw it out there anyway. Since I bought this house last April, I have been in the pool one single time. And it was to fish a screwdriver out of the water....LOL. So there has NO person in the pool the entire time. No kids, no dogs, no suntan lotion, etc. Just my mother and three dogs living here and they think that big tub of water is the entrance to the land of monsters I am convinced. They avoid going near it altogether. I have been caring for well over 100 baby toads in the pool during toad and frog season and have been using sliced up pool noodles as makeshift frog ferries for them to sit on until I can help them get back out each morning. But I believe the chlorine is now killing them sadly. I don't have any ladders but do have a pool light. Everything else in the pool is plaster.

The heat is causing me to lose about 3-4" of water each day so I am adding water every morning. I have attached a photo of the pool just to give you a little visual aide.

 

[bkfamily1]

Wow - that is a really nice looking pool. I can't believe you are leaving it to the toads! I would be evicting their little butts and having a swim every day! I suppose the toads are probably not wearing any suntan lotion, but they may be peeing and spitting (and God knows what else) in it. If there are numerous baby toads, I may not want to know what the momma and daddy toads have been up to!

 

[katwar]

Here is the history of my chlorine levels and amounts added since the re-fill was complete. Sorry the times aren't consistent each day but hopefully you will be able to see the responses to bleach each day.

7-17-15
7 pm - pool fill complete
8 pm - Added 242 oz of 8.25% bleach

7-18-15
9 am - FC 6
2 pm - FC 2 Sat index .15
5:30 pm - Added 121 oz of 8.25% bleach

7-19-15
11:30 am - FC 3.5
4:00 pm - FC 1.5
4:30 pm - Added 121 oz of 8.25% bleach

7-20-15
8:30 am - FC 6
5:30 pm - FC 3
6:00 pm - Added 121 oz of 8.25% bleach

7-21-15
10:30 am - FC 6.5

- - - Updated - - -

Too funny. Well then I wish I had their lifestyle right now then. Can't get in pool because my mom is bedridden and constantly trying to put her legs through hospital bedrails, or trying to climb out of bed, etc. When I step outside it's for 2-3 minutes at a time and then back in to check her and run back out for 2-3 more minutes. Wish I could get in the pool, and I will be able to someday soon likely. Mom is priority of course. Trying to get sod down also and that is the ugly mess on the far side of the pool. And next is getting rid of all of the mold and mildew on fence and pool deck from horrible humidity here.

 

[chem geek]

Depending on how much of the Jack's Magic Yellow Out that you used, you temporarily turned your pool into a bromine pool and bromine does not bind to CYA so is not protected from breakdown from sunlight though it does breakdown more slowly than unprotected (i.e. no CYA) chlorine. So at least part of your higher than normal chlorine demand may be from still having bromide in the pool so anytime you add chlorine it gets converted to bromine. The only way to get rid of it is by water dilution or eventually it slowly outgasses away over months. This is why we generally do not recommend using sodium bromide products in pools. Doing an OCLT would help determine whether your pool's chlorine demand is mostly during the day so likely from the sodium bromide you added vs. having something growing in your pool which would also show up as chlorine demand overnight.

A 121 fluid ounce (slightly less than a gallon) jug of 8.25% bleach in 23,000 gallons would be 3.6 ppm FC which would be on the high side given your 60 ppm CYA level. Normal usage is usually in the 2-3 ppm FC range per day. At $3 per jug that would be $51 to $76 per month. So 7 months would be $357 to $532. The lowest price I could find on 3" pucks for 50 pounds is either Leslie's at $125 or poolgeek.com at $130. 50 pounds over 7 months in 23,000 gallons implies 238 ppm FC so only 1.1 ppm FC per day. The only way you were able to have such low chlorine usage is that your FC/CYA ratio was much lower, probably half the recommended level to prevent algae growth. You mentioned that you also bought and added shock product but I don't know specifically what that was.

In factoring costs you aren't accounting for pH and TA adjustment that is required when using net acidic products such as Trichlor. The pH Up product you probably bought and added usually adds at least 60% if not 100% to the cost of the Trichlor alone.

So what happened is that your use of Trichlor had the CYA level build up over time and since you did not proportionally raise the FC level then algae started to grow resulting in higher chlorine demand resulting in no chlorine. The algae may not have yet been visible or maybe they are related to the yellow spots you had but in any event your zero chlorine in spite of adding chlorine to the pool and having high CYA is indicative of something organic growing in your pool and most likely it was algae. So yes, the Trichlor saved you on cost in the short-run, but you ended up with problems in the long-run so you need to factor that into to your total costs, including the cost and hassle of water replacement to try and keep the CYA lower.

If the bleach costs are still too high for you assuming you get into the 2-3 ppm FC per day range, then the only way to get that lower is to use supplemental products but those themselves have cost associated with them. For example, a weekly Polyquat 60 algaecide or use of a phosphate remover would be extra cost but then you'd be able to target a lower FC/CYA ratio that would use less chlorine per day, probably down to around the 1 ppm FC per day you had before. That would cut chlorine bleach cost down to around $25 per month or $175 for 7 months. You might have some need for adding acid so that would be some extra cost to add on top of this and of course the Polyquat or phosphate remover are not cheap. Polyquat 60 in a maintenance dose of 6.9 fluid ounces per week would cost $3.62 per week so $15.51 per month raising your 7 month total to $284. The phosphate remover might be more of a one-time cost if you don't have phosphates in your fill water or don't get a lot of evaporation and refill.

So you can see that there's no free lunch here and that you were fooled into thinking you were saving money with Trichlor when in reality after adding all costs in it wasn't any better and had the side effects of rising CYA. Of course at this point you need to get to a normal chlorine demand but given what you did with sodium bromide that may take months to get rid of. This is why we never, ever, blindly add products to a pool. Some of them have serious side-effects (e.g. sodium bromide increasing chlorine demand, copper staining plaster or turning blond hair green, etc.).

 

[katwar]

Leslie's has their 50 lb tubs of 3" pucks for $99 periodically and that's when I bought it....LOL. Not a huge deal but wanted to mention it. I use granular shock on average of once a month when my chlorine levels would get down kind of low. I'm not sure what you mean by pH up product. I haven't ever put anything in the pool except for chlorine pucks, granular shock and the Yellow Stuff only just recently. I added 8 oz of the Jacks stuff. So far haven't had to buy or use any Muriatic acid or baking soda or any of the things I see that are needed to resolve other issues. I had my inline chlorinator set to 3 (out of 5) and went through about 4 pucks every 10-14 days or so. Added two cups of shock every 3-4 weeks or so. Dang, I wished I would have been logging all of this stuff now. Never thought I would have a need to do it. But I'm sure as heck doing it now with the new system....hahaha.

 

[katwar]

ChemGeek, I posted my chlorine usage since the refill in another message just a few minutes ago. Not sure if you saw that or not. Is that enough to tell you whether I need to SLAM or not? I plan on going in and reading all about the CYA/chlorine relationship and try to determine if I do need to do a SLAM or not. And just to clarify, I do plan on going through with using liquid chlorine regardless of cost at this point, for at least a few more weeks or maybe a month. I will be trying to continually turn over the pool water a little at a time as well. I feel like I need to stick with this now since I have invested so much time in trying to educated myself (thanks to all of you) and fully understand the whole concept. I have no doubts that this system works fully and wonderfully. However, cost was appearing to be significantly higher and that kind of gave me reason for pause at one point. But I think I now understand why I am needing so much bleach and I'm hopeful that by continuing to do everything necessary to get my pool to a fully healthy state, the need for so much chlorine will in time be reduced a bit. Wanted to clarify this because I didn't want anything I've said to possibly come across as sounding negative or argumentative. Sometimes I just need someone to play devils advocate with me to allow me to better understand things that I have missed in the learning process.

- - - Updated - - -

Bkfamily1, here's my proof I wasn't joking about the frog ferries. One lone passenger on this particular ferry. I've got a video of a full ferry pulling up to the dock but doubt I can post it on here.

Wow - that is a really nice looking pool. I can't believe you are leaving it to the toads! I would be evicting their little butts and having a swim every day! I suppose the toads are probably not wearing any suntan lotion, but they may be peeing and spitting (and God knows what else) in it. If there are numerous baby toads, I may not want to know what the momma and daddy toads have been up to!

 

[bkfamily1]

honestly, looking at those numbers, it does not look all that bad

7/18 2pm you are at 2 and add a jug that should take you to 5.5 per PoolMath (based on the 23K gal in your signature)
7/19 11:30am you are at 3.5 which is only down 2 from the theoretical 5.5 from the prior afternoon after at least 11 or 12 hours of daylight - that is only half what you lost in 5 hours of daylight on the 18th and the same as what you lost in 4 1/2 hours on the 19th

7/19 4pm you are at 1.5 and add a jug that should get you to 5
7/20 8:30am you are at 6 - no loss from the theoretical 5 from the prior afternoon, in fact it is higher

7/20 5:30pm you are at 3 and add a jug which should get you to 6.5
7/21 10:30am you are still at 6.5, unchanged from what one would expect from the previous day's result and the bleach you added

Maybe I am missing something, but I am not seeing big drops from what you would initially expect. However, none of these are after dark or before first light. The best way to know if anything is going on would be an OCLT. You may find that all is actually good. And it may be that the FC loss is just happening during the day, maybe due to long hours of intense sunlight.

Is this FC usage different than what you saw previously?

 

[katwar]

I can't honestly answer your question because I didn't keep track of my FC usage when I was using pucks and shock. I only tested about once a week to determine if I needed to shock and make sure overall chemistry was okay. I checked the chlorinator every week or so to make sure there were still pucks in it and that was about it. So I don't know how much chlorine I went through per day or overnight. But yes, the UV levels here this time of year are incredible. Would it be advantageous then for me to try and take my readings at night and should those evening readings be just before I add the bleach? Or would you like to see the levels just after adding the bleach or an hour or so after adding the bleach? Just let me know and I would more than happy to try and do that for several days if that would show a more accurate picture. And I can also try and get earlier readings in the morning.

honestly, looking at those numbers, it does not look all that bad

7/18 2pm you are at 2 and add a jug that should take you to 5.5 per PoolMath (based on the 23K gal in your signature)
7/19 11:30am you are at 3.5 which is only down 2 from the theoretical 5.5 from the prior afternoon after at least 11 or 12 hours of daylight - that is only half what you lost in 5 hours of daylight on the 18th and the same as what you lost in 4 1/2 hours on the 19th

7/19 4pm you are at 1.5 and add a jug that should get you to 5
7/20 8:30am you are at 6 - no loss from the theoretical 5 from the prior afternoon, in fact it is higher

7/20 5:30pm you are at 3 and add a jug which should get you to 6.5
7/21 10:30am you are still at 6.5, unchanged from what one would expect from the previous day's result and the bleach you added

Maybe I am missing something, but I am not seeing big drops from what you would initially expect. However, none of these are after dark or before first light. The best way to know if anything is going on would be an OCLT. You may find that all is actually good. And it may be that the FC loss is just happening during the day, maybe due to long hours of intense sunlight.

Is this FC usage different than what you saw previously?