I will add, I have many pools and with that said when I come upon a high CYA I make them bite the bullet with a proper drain and fill. TFP works hands down and the proof is in the pudding. Get the CYA where it needs to be and life gets much easier pool wise. Follow here to the "T" and you'll see that pool management is very simple.
first time tf100 questions
- Thread starter sdtfp
- Start date
Thanks for taking the time to answer my questions! Can I ask where you got that 7.5% rule? I'll google it now, but just in case you had it handy. That rules doesn't really reflect what I've seen in the pool. I have tests in the range of 160-180. And I've never seen the FC above 9. Of course, the test results are in question here! So would not keeping the 7.5 rule have any immediate effects? IF my test results are good, I'm running at or below 5% of CYA. And most likely for many weeks without any side effect. If it would have any immediate effects, then I can now say that my CYA levels are a lot lower then what the tests are showing.
This brings me back to around 2 weeks ago when CYA test result showed 46. Maybe thats closer to the truth. Anyway I can narrow this down? Pool stores tests are bad, my own tests arent matching the 7.5% rule. Evaporation seems to be reducing CYA. Water looks fine. Doesn't seem like I can get a handle on how to accurately test CYA.
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- May 3, 2014
- 58,451
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Just to follow up on what @magiteck commented on.
Liquid Chlorine neithers increases or decreases CYA. Chlorine pucks can increase CYA. If you have ever increasing CYA then you require more chlorine (higher ppm) to maintain a safe sanitized pool. Refer to the FC/CYA Levels that you read your CYA (per your test) then dose your pool to reach the target Chlorine PPM. Lower Chlorine does NOT mean lower CYA. If you have high CYA then you need higher Chlorine.
As you stated, you will need to do a partial drain to get your CYA down to the 40-50 range.
With regard to cost of Liquid Chlorine, if you use the Pool Math app there is a "Bleach $ Calculator" under the main menu. You input the cost, set the volume you are purchasing and set the % Chlorine. This allows you to compare 6% Chlorine to 10% chlorine to 12.5% chlorine. At Leslies I can buy 12.5% CL but at Home Depot it is 10% CL. In Houston TX the %CL price are about identical, but that could be different in other parts of USA. Also, you must remember that to increase the same value of PPM (lets say you want to increase your CL by 2 PPM over what you tested it at). Then you will need to add more volume of 10% Cl than 12.5% CL. This is why the Bleach Calculator is helpful. Whichever % is lower unit cost then that would be the preferred CL to use. Hope this makes sense.
Liquid Chlorine neithers increases or decreases CYA. Chlorine pucks can increase CYA. If you have ever increasing CYA then you require more chlorine (higher ppm) to maintain a safe sanitized pool. Refer to the FC/CYA Levels that you read your CYA (per your test) then dose your pool to reach the target Chlorine PPM. Lower Chlorine does NOT mean lower CYA. If you have high CYA then you need higher Chlorine.
As you stated, you will need to do a partial drain to get your CYA down to the 40-50 range.
With regard to cost of Liquid Chlorine, if you use the Pool Math app there is a "Bleach $ Calculator" under the main menu. You input the cost, set the volume you are purchasing and set the % Chlorine. This allows you to compare 6% Chlorine to 10% chlorine to 12.5% chlorine. At Leslies I can buy 12.5% CL but at Home Depot it is 10% CL. In Houston TX the %CL price are about identical, but that could be different in other parts of USA. Also, you must remember that to increase the same value of PPM (lets say you want to increase your CL by 2 PPM over what you tested it at). Then you will need to add more volume of 10% Cl than 12.5% CL. This is why the Bleach Calculator is helpful. Whichever % is lower unit cost then that would be the preferred CL to use. Hope this makes sense.
New test results from pool store today.
FC 4.14, PH 8, TA 76, CYA 144, Phos 3397
My 120 CYA TF100 test result I think was a little off because I rounded up to the 60 line, where I think I should of estimated closer to 65 or 70. I read your supposed to round to nearest line, but since numbers increase down, maybe I need to round up to a number and not the line?
Anyhow, looks like I've dropped FC by almost half since I started this journey a few days ago. Water still looks perfect. CYA still high. Still can't figure out if I have a problem...
Anyhow to be on the safe side, I'm going to be adding some liquid chlorine in a bit. Maybe raise it to 5? I got it from home depot since pool store said they were out. Funny thing about the guy at the pool store; I started talkign to him about my CYA and he agreed it was a problem and I should drain/fill but he quickly moved on to push nophos on me. Said that was what he was worried about the most. I was merciful and didnt point out to him that he had just told me I need a drain/fill, which would solve most of my phos "problem." He warned my pool will be a swap when I open in the spring if I don't take care of that. I didn't bite... time will tell if he was right.
A couple of questions I had...
1. Would cleaning out my DE filter remove CYA? So if I started cleaning it weekly, would I make a dent on CYA?
2. For a pool my size, how much can I lower the water level on closing? I think we did 12 inches under tile line last year. Can I got 16 inches or 18? This way if it rains, I don't have to drain it over the fall/winter. I've heard if you drain a pool too much, the weight of the pool is too low for the ground and it may move or something? After how many inches is that a problem? Any other problems from draining too much on closing?
3. What should my FC be during the offseason when pool is closed? It's covered and im in the NE so chlorine wont evaporate much. MAybe the pool will even freeze, so maybe that stops the loss of FC? Or maybe that kills all algea anyways and even FC of 0 wont matter??
4. Anything I should tell the pool pros when they close the pool? I guess I will tell them not to add chlorine tabs. Not sure they would anyways since the pump will be disconnected.
5. Should I add muriatic acid now or ask pool pros to do it when closing the pool in the next week or two? Does PH even matter when pool is closed?
FC 4.14, PH 8, TA 76, CYA 144, Phos 3397
My 120 CYA TF100 test result I think was a little off because I rounded up to the 60 line, where I think I should of estimated closer to 65 or 70. I read your supposed to round to nearest line, but since numbers increase down, maybe I need to round up to a number and not the line?
Anyhow, looks like I've dropped FC by almost half since I started this journey a few days ago. Water still looks perfect. CYA still high. Still can't figure out if I have a problem...
Anyhow to be on the safe side, I'm going to be adding some liquid chlorine in a bit. Maybe raise it to 5? I got it from home depot since pool store said they were out. Funny thing about the guy at the pool store; I started talkign to him about my CYA and he agreed it was a problem and I should drain/fill but he quickly moved on to push nophos on me. Said that was what he was worried about the most. I was merciful and didnt point out to him that he had just told me I need a drain/fill, which would solve most of my phos "problem." He warned my pool will be a swap when I open in the spring if I don't take care of that. I didn't bite... time will tell if he was right.
A couple of questions I had...
1. Would cleaning out my DE filter remove CYA? So if I started cleaning it weekly, would I make a dent on CYA?
2. For a pool my size, how much can I lower the water level on closing? I think we did 12 inches under tile line last year. Can I got 16 inches or 18? This way if it rains, I don't have to drain it over the fall/winter. I've heard if you drain a pool too much, the weight of the pool is too low for the ground and it may move or something? After how many inches is that a problem? Any other problems from draining too much on closing?
3. What should my FC be during the offseason when pool is closed? It's covered and im in the NE so chlorine wont evaporate much. MAybe the pool will even freeze, so maybe that stops the loss of FC? Or maybe that kills all algea anyways and even FC of 0 wont matter??
4. Anything I should tell the pool pros when they close the pool? I guess I will tell them not to add chlorine tabs. Not sure they would anyways since the pump will be disconnected.
5. Should I add muriatic acid now or ask pool pros to do it when closing the pool in the next week or two? Does PH even matter when pool is closed?
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I am somewhat butting into this thread but you should STAY OUT OF THE POOL STORE. Any test you get from them is unreliable and will only get you confused.
Additionally, from a few of your comments, I do not think you yet have a good grasp of just what these parameters are that we test for and what they do and how to adjust them, I urge you to Please read "The "ABC's of Pool Water Chemistry" up in Pool School........you need a better understanding of the chemistry before you attempt to adjust it.
Additionally, from a few of your comments, I do not think you yet have a good grasp of just what these parameters are that we test for and what they do and how to adjust them, I urge you to Please read "The "ABC's of Pool Water Chemistry" up in Pool School........you need a better understanding of the chemistry before you attempt to adjust it.
Just a couple of quick points to your memo above.
Always round down to the highest CYA - if you reading between 2 lines go to the higher CYA number. I test by going to the line where I can still see then I add the sample to the next line. If I can see the dot I then add more sample to the next line. If I cannot see the dot then the CYA is at my previous point. For example I pour to 80 line and I see the dot, then I pour to the 70 line. If at the 70 line I can still see it I pour again to 60 line, if I do not see it at the 70 line then my CYA is 80. That way I am not trying to interpret between 70 and 80.
Then go to the FC/CYA Levels and I pour liquid chlorine to reach the minimum target amount.
CYA can not be removed by the filter. Cleaning your DE filter is good practice but probably only 1 or 2 times a year if you back wash it every 4-6 weeks. Some people skip the backwash and just clean the filter as needed. You need to watch the pressure of your filter to monitor how long it takes to increase 25% over the initial "clean" filter. So if you clean your filter and it operates at 10psi then at around 12-14psi you may want to back wash. Some delay to 5psi increments. You need to establish how often you want to clean your DE filter. I backwash on a monthly cycle and do a complete clean twice a year. But that is how I like to do it and it works for my pool with debris, etc.
It always fun talking to pool store people as they are always trying to push something. Glad you did not bite!!
I don't have to close my pool so I let others respond to your specific questions on that.
Always round down to the highest CYA - if you reading between 2 lines go to the higher CYA number. I test by going to the line where I can still see then I add the sample to the next line. If I can see the dot I then add more sample to the next line. If I cannot see the dot then the CYA is at my previous point. For example I pour to 80 line and I see the dot, then I pour to the 70 line. If at the 70 line I can still see it I pour again to 60 line, if I do not see it at the 70 line then my CYA is 80. That way I am not trying to interpret between 70 and 80.
Then go to the FC/CYA Levels and I pour liquid chlorine to reach the minimum target amount.
CYA can not be removed by the filter. Cleaning your DE filter is good practice but probably only 1 or 2 times a year if you back wash it every 4-6 weeks. Some people skip the backwash and just clean the filter as needed. You need to watch the pressure of your filter to monitor how long it takes to increase 25% over the initial "clean" filter. So if you clean your filter and it operates at 10psi then at around 12-14psi you may want to back wash. Some delay to 5psi increments. You need to establish how often you want to clean your DE filter. I backwash on a monthly cycle and do a complete clean twice a year. But that is how I like to do it and it works for my pool with debris, etc.
It always fun talking to pool store people as they are always trying to push something. Glad you did not bite!!
I don't have to close my pool so I let others respond to your specific questions on that.
- Jun 22, 2014
- 47,841
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
I'll chime in for the first time to answer a couple of your questions and reiterate what some others have said:
1. Drop the pool store testing. It's only making things worse. You have a TF-100 - trust it and your testing. If you ever have a doubt about ANY test, we're here to help. But from now own, you have to post just your numbers as no one is going to trust the pool store tests.
2. CYA does not evaporate. A minimal amount may go down if you do a lot of backwashing. A small amount of CYA (about 5 ppm) may get used-up each month through consumption, but all of that is very slow. The most effective way to reduce CYA is by water exchange. Once you do that, and get the CYA to a manageable number (i.e. 50), it will never go up again unless you want it to.
3. Pool pros? Be warned. Not all of them are pros. Certainly there are some good pool techs out there, but there are many techs who are just seasonal employees or only taught something by another employee - and that other employee may not know proper chemistry. There's no reason (with your TF-100) why you can't manage the chemicals year-round and for closing. Just let the techs do the physical part of blowing out the lines, etc.
4. Lowering your water for closing varies by pool type and whether it may be covered. For yours, the techs may lower it below the returns to blow out the lines, or they may use specialized plugs and leave some things submerged. They may also take the water below the skimmer and prep that area as well. As long as they don't drain much more below the return jets your pool should be fine. By the way, lowering some of that water will also help to lower your CYA for next year.
5. At closing, your FC should be close to SLAM level per the FC/CYA Levels. Once the pool is shut down and covered, nothing else will matter until spring.
I can't emphasize enough - trust your own TF-100 test results. See the link below about closing, if not for the physical parts, at least for the chemistry. Get the chemistry right before they show-up to close and you should be good. If you have questions, just ask.
www.troublefreepool.com
1. Drop the pool store testing. It's only making things worse. You have a TF-100 - trust it and your testing. If you ever have a doubt about ANY test, we're here to help. But from now own, you have to post just your numbers as no one is going to trust the pool store tests.
2. CYA does not evaporate. A minimal amount may go down if you do a lot of backwashing. A small amount of CYA (about 5 ppm) may get used-up each month through consumption, but all of that is very slow. The most effective way to reduce CYA is by water exchange. Once you do that, and get the CYA to a manageable number (i.e. 50), it will never go up again unless you want it to.
3. Pool pros? Be warned. Not all of them are pros. Certainly there are some good pool techs out there, but there are many techs who are just seasonal employees or only taught something by another employee - and that other employee may not know proper chemistry. There's no reason (with your TF-100) why you can't manage the chemicals year-round and for closing. Just let the techs do the physical part of blowing out the lines, etc.
4. Lowering your water for closing varies by pool type and whether it may be covered. For yours, the techs may lower it below the returns to blow out the lines, or they may use specialized plugs and leave some things submerged. They may also take the water below the skimmer and prep that area as well. As long as they don't drain much more below the return jets your pool should be fine. By the way, lowering some of that water will also help to lower your CYA for next year.
5. At closing, your FC should be close to SLAM level per the FC/CYA Levels. Once the pool is shut down and covered, nothing else will matter until spring.
I can't emphasize enough - trust your own TF-100 test results. See the link below about closing, if not for the physical parts, at least for the chemistry. Get the chemistry right before they show-up to close and you should be good. If you have questions, just ask.
Closing an In Ground Pool
Winterizing a pool is essential for keeping your in-ground pool protected during cold-weather months. This Pool Repair guide will show you how to do it.
www.troublefreepool.com
- May 20, 2020
- 1,001
- Pool Size
- 13600
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- Solaxx (Saltron) Reliant / Purechlor R5
I second @duraleigh recommendation to read through ABCs of Pool Water Chemistry. The comment about trying to aim for a FC of 5 tells me it’s not quite clicking yet. 5 is way too low for your CYA level.
You’ve been lucky so far. Going below minimum FC doesn’t mean algae will magically form, but it does mean conditions are right for it to do so. And if you get algae in your pool at this CYA level, you will not be able to get rid of it and you’ll be forced to rapidly drain.
If you’re not going to drain/refill to lower the CYA to recommended range, you really need to keep your FC above that minimum 7.5% CYA. Others have correctly advised you to round up on the CYA test, which puts you at 140, and means your FC needs to be above 10.5 at the minimum.
SLAM level, which was mentioned as the ideal level to reach prior to closing is 56ppm FC at 140 CYA.
You seem to have the old wisdom in your mind that chlorine above 3 is “high”. It’s not, when you have CYA binding to all of it and preventing it from disinfecting. The article linked earlier by @mknauss does a great job of explaining the science.
You’ve been lucky so far. Going below minimum FC doesn’t mean algae will magically form, but it does mean conditions are right for it to do so. And if you get algae in your pool at this CYA level, you will not be able to get rid of it and you’ll be forced to rapidly drain.
If you’re not going to drain/refill to lower the CYA to recommended range, you really need to keep your FC above that minimum 7.5% CYA. Others have correctly advised you to round up on the CYA test, which puts you at 140, and means your FC needs to be above 10.5 at the minimum.
SLAM level, which was mentioned as the ideal level to reach prior to closing is 56ppm FC at 140 CYA.
You seem to have the old wisdom in your mind that chlorine above 3 is “high”. It’s not, when you have CYA binding to all of it and preventing it from disinfecting. The article linked earlier by @mknauss does a great job of explaining the science.
CraigChing
Gold Supporter
- Jun 15, 2019
- 202
- Pool Size
- 22000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
I agree with what everyone else is saying 100%, I’m only quoting this because I shared my experience earlier in the thread managing high CYA.
1. I readily admit I was probably lucky this summer maintaining lower FC than what my CYA said I should.
2. If I ended up with algae or cloudiness, my first action would have been a water exchange. I bought a 1/2 HP pump just in case! (And got to use it when a pump drain plug exploded and I decided to drain down past my returns to move the needle on CYA again since I didn’t have a spare plug and had to order one from amazon which gave me a couple of days of pump downtime)
3. The only element of my luck I tried to mitigate was in testing *with my own test kit* and adjusting FC with liquid chlorine *daily*. No short cuts here.
I really hope my share of how I’m managing high CYA didn’t provide any misconceptions. I fully advocate for TFP methods, but my reality this year afforded me a little wiggle room that I will reconcile next year.
CraigChing
Gold Supporter
- Jun 15, 2019
- 202
- Pool Size
- 22000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Honestly, for 2. above, in retrospect, I wish I'd done the “no drain water exchange” at that point, but I was nervous being down my pump and not sure how long it would be out of service. I almost hoped my pool would turn cloudy at that point so I would have been justified 
Thanks for the replies everyone, it's very helpful!
I did reread the abcs of pool water chemistry. I think I get it and have gotten it. The problem is that my pool has been so good and clear. All season it's been perfect with FC around 8. So maybe i've been lucky or maybe the CYA testing is off. I don't really trust my CYA test results! So reality is not matching what you guys are saying. Well at least until today...
Today's update..
I did tests and results are:
FC 5.5 (up from 4.14 (pool store) after adding 24 oz of 10% liquid chlorine yesterday)
CC 0.5 or less as very slightly pink
TA - 120
CYA 150
PH 7.9
But the big news is that I looked at the pool a few times and found some algea I think! It was like yellow(maybe green?) spots. I used the brush and they seemed to go away. My pool has a decent amount of stains on the bottom so it was hard to be sure, but im 90% sure. The water was not cloudy. So even though my FC went over 1+ ppm over night, the algea arrived. I did not add anymore chlorine as I was busy and I also wanted to ask here.
So how should I proceed? I read the SLAM guide here, which says my CYA is too high to do SLAM. Also, it says if pool is green.. but my pool isn't green ..So I think I have two options...
First option is to "drain and SLAM with shock granules"
1. Lower PH to 7.2 with muriatic acid.
2. Run pump 24/7?
3. Partially drain pool for an hour and then refill. I have https://www.amazon.com/gp/product/B000X07GQS/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 . Says 2400 gallons per hour. I can't run pump at this time since water will fall below skimmer correct?
4. Add shock granules to get high 54 FC? I have no experience raising FC this high.
5. repeat steps 3 and 4 every day until pool is clear
Second option is just to shock with liquid chlorine. This seems like a better option just because my pool is clear....
1. lower ph to 7.2
2. Add liquid chlorine to get to around ~30 ppm. I'm guessing much more than this will be hard with liquid chlorine.
3. If the next day is not clear then go to "drain and SLAM with shock granules"
Would it be worth it to try this first?
For the daily SLAM method, how do I know when to stop if my water stays clear? How long after adding muriatic acid should I test ph and then how long after ph is 7.2 before I start adding shock or chlorine?
Also, the pool can be used the next day even with high FC correct?
Some questions...
I did reread the abcs of pool water chemistry. I think I get it and have gotten it. The problem is that my pool has been so good and clear. All season it's been perfect with FC around 8. So maybe i've been lucky or maybe the CYA testing is off. I don't really trust my CYA test results! So reality is not matching what you guys are saying. Well at least until today...
Today's update..
I did tests and results are:
FC 5.5 (up from 4.14 (pool store) after adding 24 oz of 10% liquid chlorine yesterday)
CC 0.5 or less as very slightly pink
TA - 120
CYA 150
PH 7.9
But the big news is that I looked at the pool a few times and found some algea I think! It was like yellow(maybe green?) spots. I used the brush and they seemed to go away. My pool has a decent amount of stains on the bottom so it was hard to be sure, but im 90% sure. The water was not cloudy. So even though my FC went over 1+ ppm over night, the algea arrived. I did not add anymore chlorine as I was busy and I also wanted to ask here.
So how should I proceed? I read the SLAM guide here, which says my CYA is too high to do SLAM. Also, it says if pool is green.. but my pool isn't green ..So I think I have two options...
First option is to "drain and SLAM with shock granules"
1. Lower PH to 7.2 with muriatic acid.
2. Run pump 24/7?
3. Partially drain pool for an hour and then refill. I have https://www.amazon.com/gp/product/B000X07GQS/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 . Says 2400 gallons per hour. I can't run pump at this time since water will fall below skimmer correct?
4. Add shock granules to get high 54 FC? I have no experience raising FC this high.
5. repeat steps 3 and 4 every day until pool is clear
Second option is just to shock with liquid chlorine. This seems like a better option just because my pool is clear....
1. lower ph to 7.2
2. Add liquid chlorine to get to around ~30 ppm. I'm guessing much more than this will be hard with liquid chlorine.
3. If the next day is not clear then go to "drain and SLAM with shock granules"
Would it be worth it to try this first?
For the daily SLAM method, how do I know when to stop if my water stays clear? How long after adding muriatic acid should I test ph and then how long after ph is 7.2 before I start adding shock or chlorine?
Also, the pool can be used the next day even with high FC correct?
Some questions...
I am not sure where you picked up "shock granules" for the SLAM but please don't use them. Liquid chlorine simply is much easier to SLAM with.
The Pool Store results you post are meaningless to us. Manage your pool however you see fit, but pool store advice and tests is simply disregarded by anyone on TFP that understands this stuff.
The Pool Store results you post are meaningless to us. Manage your pool however you see fit, but pool store advice and tests is simply disregarded by anyone on TFP that understands this stuff.
Just an update for anyone looking at this in the future..
I ended up draining about 15% of the pool. I had wanted to do more but that took a lot longer than I anticipated. Turns out the per gallon rate of the pump is based on the length of the hose. And I used a 50 ft hose which is really slow. Next time I drain, I will plan for a multi day event.
After adding the water back, I shocked it to FC 30 with 12.5% liquid chlorine from pool store, but I didn't measure it right away so not sure how accurate I was. I measured the CYA and I got around 130. So I went from around 140/150 to 130/140. Not much of a difference but sorta inline with what is expected. Next time I measured the FC it was like 10 hours later at night. I got FC of 26 and CC of .5. The next morning the OCLT came back at FC of 25 and CC of 0.
As you might have noticed, I didn't shock at 54 which what was recommended for my high level of CYA. The water was clear and I didn't have any algea so I figured that shocking it around 30 would be good enough and I could always up it to 54 if the OCLT has failed. Next time I will probably go to 54, now that I am more confident in my chlorine measurements and I would want to see how the pool looks after that. But I don't plan to continue the SLAM as the OCLT was 1 ppm and water looks good. The only thing I noticed preshock was that the pool looked a bit dull after adding water. But it was a cloudy day and summer is pretty much done here, so that might have something to do with it. Also, our tap water here is often cloudy (fluride?) so I guess that was it. Today it doesn't look dull anymore. So either the filter did its job and took out algeo or whatever was in the pool and/or its a nicer day for the pool to look good.
some takeaways for me:
1. Buy r-0871... testing at crazy high FC levels requires a lot of drops
2. 8 FC is probably good enough for my pool until I get the time to drain the pool.. it was perfect all season and I was able to drop it to 4 FC without any problem. This may just be because my pool is just better at resisting algea then the normal. But I do plan to drain it over time and get to more normal levels as conditions might change over time and lower levels will give me more flexibility to fix any bacteria issues.
3. I had reported yellow algea at around 4.5 FC, but now im not so sure. I read pollen can look like that. It's not pollen time but I have some flowers that have a lot of pollen right now. Which I noticed the other day and I was wondering why in the world would these flowers have so much pollen now instead of being dead.
4. I found that some sites say to shock at CC level times 10. Whereas this site had a chart based on CYA. I don't know the difference...
5. knowing about the OCLT (overnight chlorine loss test) is pretty big as it something to test for when you have clear water. I think this was my biggest problem, I had clear water so no way to say my pool had any definite problems. Maybe someone recommended it on this thread and I missed it, but I wish I had done an OCLT prior to shocking. I was to busy figuring out how to shock, that I didn't run into the OCLT until I finished adding the huge amount of chlorine and asking myself.. "now what".
I ended up draining about 15% of the pool. I had wanted to do more but that took a lot longer than I anticipated. Turns out the per gallon rate of the pump is based on the length of the hose. And I used a 50 ft hose which is really slow. Next time I drain, I will plan for a multi day event.
After adding the water back, I shocked it to FC 30 with 12.5% liquid chlorine from pool store, but I didn't measure it right away so not sure how accurate I was. I measured the CYA and I got around 130. So I went from around 140/150 to 130/140. Not much of a difference but sorta inline with what is expected. Next time I measured the FC it was like 10 hours later at night. I got FC of 26 and CC of .5. The next morning the OCLT came back at FC of 25 and CC of 0.
As you might have noticed, I didn't shock at 54 which what was recommended for my high level of CYA. The water was clear and I didn't have any algea so I figured that shocking it around 30 would be good enough and I could always up it to 54 if the OCLT has failed. Next time I will probably go to 54, now that I am more confident in my chlorine measurements and I would want to see how the pool looks after that. But I don't plan to continue the SLAM as the OCLT was 1 ppm and water looks good. The only thing I noticed preshock was that the pool looked a bit dull after adding water. But it was a cloudy day and summer is pretty much done here, so that might have something to do with it. Also, our tap water here is often cloudy (fluride?) so I guess that was it. Today it doesn't look dull anymore. So either the filter did its job and took out algeo or whatever was in the pool and/or its a nicer day for the pool to look good.
some takeaways for me:
1. Buy r-0871... testing at crazy high FC levels requires a lot of drops
2. 8 FC is probably good enough for my pool until I get the time to drain the pool.. it was perfect all season and I was able to drop it to 4 FC without any problem. This may just be because my pool is just better at resisting algea then the normal. But I do plan to drain it over time and get to more normal levels as conditions might change over time and lower levels will give me more flexibility to fix any bacteria issues.
3. I had reported yellow algea at around 4.5 FC, but now im not so sure. I read pollen can look like that. It's not pollen time but I have some flowers that have a lot of pollen right now. Which I noticed the other day and I was wondering why in the world would these flowers have so much pollen now instead of being dead.
4. I found that some sites say to shock at CC level times 10. Whereas this site had a chart based on CYA. I don't know the difference...
5. knowing about the OCLT (overnight chlorine loss test) is pretty big as it something to test for when you have clear water. I think this was my biggest problem, I had clear water so no way to say my pool had any definite problems. Maybe someone recommended it on this thread and I missed it, but I wish I had done an OCLT prior to shocking. I was to busy figuring out how to shock, that I didn't run into the OCLT until I finished adding the huge amount of chlorine and asking myself.. "now what".
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BenB
Gold Supporter
- Jul 24, 2020
- 277
- Pool Size
- 19500
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Jandy Aquapure 1400
As a brand new and uninvited voice to this thread, a couple of observations from reading through all the back and forth.
edit: My joke got ruined by the auto censor. So I fixed it.
- I know... It's the internet and as the expression goes - "Opinions are like a-holes. Everybody has one." But as somebody said above, you really, really do have to just 'buy in' to the TFP methodology if that is the path you want to follow. Mixing and matching advice and testing from various sources just means that you're not following anybody's advice completely and so nobody will be satisfied with what you're doing. Go all in, or don't. It's your pool!
- Someone else can show the math, but be advised that draining and refilling 25% of your water 4 times is not the same as draining 100% of your water once. To bring down your very high CYA, you really should just bite the bullet and do it all in one go. Otherwise you will end up probably putting in twice as much new water, and it'll take a lot longer and you'll be out of balance for an even longer time period.
- Thread after thread contain stories of 'perfectly clear water' ultimately not being so. Be careful dismissing advice with 'but everything is fine for me' as this will be met with a lot of skepticism!
edit: My joke got ruined by the auto censor. So I fixed it.
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