Pool won't hold chlorine/visual etching starting

[bkfamily1]

Kat - the key is that you want to see how much the FC drops during as long a period as possible with no sunlight and with no other changes. So you want to test the FC after dark (at least 30 minutes, preferably an hour or so after sunset - currently about 8:20pm in Houston) and and again before first light (at least 30 preferably 60+ minutes before sunrise - currently about 6:30am). You want to add any chlorine or other chemicals at least 30 preferably 60+ minutes before the night-time test, and you do not want to add anything between the two tests. Keep your pump running so the water is circulating. Do not have any automatic chemical addition going on (like the in-line chlorinator - be sure it is empty or off) between the two tests. At that point, the only thing that will affect your FC is the organics in the water. If the FC drops less than 1ppm between the tests, you do not have meaningful amounts of organics in your water. If it drops more than 1ppm, it is time to slam. Refer to the OCLT test page for more detail perform-the-overnight-fc-chlorine-loss-test-oclt and to the SLAM page if you need to SLAM your pool slam-shock-level-and-maintain-shockingl

*** please note that I completely defer to chemgeek and others with more knowledge of the bromide issue - it may be that a high OCLT result could be due to the bromide, not organics - although it sounded like chemgeek said that the high FC loss due to bromide happens in sunlight - so, chemgeek, is the OCLT still valid with the bromide situation going on?? ***

 

[katwar]

BKfamily1, I will do this tonight. I will set my alarm on both ends to make sure I encompass the longest period I can with no sunlight. This was very well worded as to what I need to do and why. Thank you for such terrific instructions. My chlorinator is empty and set in the "off" position already.

Kat - the key is that you want to see how much the FC drops during as long a period as possible with no sunlight and with no other changes. So you want to test the FC after dark (at least 30 minutes, preferably an hour or so after sunset - currently about 8:20pm in Houston) and and again before first light (at least 30 preferably 60+ minutes before sunrise - currently about 6:30am). You want to add any chlorine or other chemicals at least 30 preferably 60+ minutes before the night-time test, and you do not want to add anything between the two tests. Keep your pump running so the water is circulating. Do not have any automatic chemical addition going on (like the in-line chlorinator - be sure it is empty or off) between the two tests. At that point, the only thing that will affect your FC is the organics in the water. If the FC drops less than 1ppm between the tests, you do not have meaningful amounts of organics in your water. If it drops more than 1ppm, it is time to slam. Refer to the OCLT test page for more detail perform-the-overnight-fc-chlorine-loss-test-oclt and to the SLAM page if you need to SLAM your pool slam-shock-level-and-maintain-shockingl

*** please note that I completely defer to chemgeek and others with more knowledge of the bromide issue - it may be that a high OCLT result could be due to the bromide, not organics - although it sounded like chemgeek said that the high FC loss due to bromide happens in sunlight - so, chemgeek, is the OCLT still valid with the bromide situation going on?? ***

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Bkfamily1, you said to keep my pump running all night. Is it okay to have my Kreepy going with it or should I remove it?

 

[bkfamily1]

I would think it is fine to have Kreepy running. It does not contribute to the chemistry. The reason to keep the pump running is to keep the water circulating so the chemistry stays consistent throughout the pool. That way you get a good measure of the overall FC level at the start and finish.

 

[sbcpool]

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.

The chlorine will kill them. The skin of amphibians is very thin and permeable to many chemicals. They will absorb the chlorine from the water into their blood. You could relocate them if you want to prevent them from suffering that fate.

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.

Are you sure you don't have a leak? Even when temperatures here were over 100°F I didn't lose more than about 1/2" per day.

 

[katwar]

I actually have relocated a good bunch of them down to a neighborhood pond. Didn't realize that another 100 were waiting to come into the world right after that. It's primarily the teeny tiny babies that jump into the pool and can't get back out. Once they're a week or so old they seem to know better. So far I've only lost two since using bleach. I'm hopeful it's the end of the season for babies. It's looking that way at least. I made a note on my calendar for next year to pay attention so that I can get them relocated immediately once I start seeing them. But once they jump into the pool during the night I'm helpless. They do swim straight over to the noodles once they realize they can't get out. But once the water gets on them that's it. Will have to get creative next year with some mesh screening or something.

And I don't think I have a leak. I just went out and actually measured from my normal fill level to where it usually is at the end of the day and it's about 1 1/2". It sure looks like a lot more than that when it's lower than normal though. At least when I' standing above it. Once I got down to eye level with the tiles I could see it wasn't as much as it appears to be. Not sure if I can factor heat index into the evaporation rate or not but we've been around a 105-106 heat index the past few days also.

 

[katwar]

Bkfamily1, well this just keeps on getting more interesting. I did what you suggested and here are the results.

I believe the last level I posted on here was yesterday morning at 10:30 am my FC was 6.5

Last night at 8:10 pm my FC was 4. Not a bad drop considering the UV levels.
Based on that FC level of 4, at 8:20 pm I added 102 oz of 8.25% bleach with an FC goal of 7.
At 9:25 pm I re-tested and my FC was 8.5 (whoa).
I left the pump running all night.
At 6:15 a.m. this morning my FC was actually 9.0 (double whoa).

I know the goal is to have the FC close to what it was the evening before, but it was actually higher. And what I'm wondering is if waiting an hour just wasn't enough time to get the bleach fully distributed in the pool. The reason I suspect that is because I have four return outlets. Two are in the shallow end, a third is where the slope is going from the shallow to the deep end and fourth is in the bench seat area, only 2" above the seat itself. That's really the only one that could be considered to be in the deep end. When I get a sample to check any chemistry, I habitually use the same area in the deep end. Do you think that's a possible explanation as to why my FC levels are sometimes higher in the morning than the night before? And I guess the good news is that it "appears" that the FC level is holding overnight. So does that mean I can assume I'm algae free and start doing daily chemistry maintenance with a min FC of 5 and goal of 7? CYA is 60. And I'm also wondering since I plugged in a FC goal of 7 into the calculator last night and ended up with a FC level of 9 this morning if I should reduce that goal to 6 maybe? It appears that with each dose of liquid bleach my subsequent FC levels are getting higher and higher, which technically means a need for less for bleach perhaps. And that makes me happy...LOL.

Kathy

Kat - the key is that you want to see how much the FC drops during as long a period as possible with no sunlight and with no other changes. So you want to test the FC after dark (at least 30 minutes, preferably an hour or so after sunset - currently about 8:20pm in Houston) and and again before first light (at least 30 preferably 60+ minutes before sunrise - currently about 6:30am). You want to add any chlorine or other chemicals at least 30 preferably 60+ minutes before the night-time test, and you do not want to add anything between the two tests. Keep your pump running so the water is circulating. Do not have any automatic chemical addition going on (like the in-line chlorinator - be sure it is empty or off) between the two tests. At that point, the only thing that will affect your FC is the organics in the water. If the FC drops less than 1ppm between the tests, you do not have meaningful amounts of organics in your water. If it drops more than 1ppm, it is time to slam. Refer to the OCLT test page for more detail perform-the-overnight-fc-chlorine-loss-test-oclt and to the SLAM page if you need to SLAM your pool slam-shock-level-and-maintain-shockingl

*** please note that I completely defer to chemgeek and others with more knowledge of the bromide issue - it may be that a high OCLT result could be due to the bromide, not organics - although it sounded like chemgeek said that the high FC loss due to bromide happens in sunlight - so, chemgeek, is the OCLT still valid with the bromide situation going on?? ***

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Oh, and one more thing bkfamily1.....Chemgeek mentioned the high FC loss due to bromide typically happens in sunlight, and that would make perfect sense now since it is obvious that I am have significant FC loss during the day and none at night. I mean, I know a good chunk of that is from the UV, but factoring in the bromide would account for the drastic loss I think.

Kat - the key is that you want to see how much the FC drops during as long a period as possible with no sunlight and with no other changes. So you want to test the FC after dark (at least 30 minutes, preferably an hour or so after sunset - currently about 8:20pm in Houston) and and again before first light (at least 30 preferably 60+ minutes before sunrise - currently about 6:30am). You want to add any chlorine or other chemicals at least 30 preferably 60+ minutes before the night-time test, and you do not want to add anything between the two tests. Keep your pump running so the water is circulating. Do not have any automatic chemical addition going on (like the in-line chlorinator - be sure it is empty or off) between the two tests. At that point, the only thing that will affect your FC is the organics in the water. If the FC drops less than 1ppm between the tests, you do not have meaningful amounts of organics in your water. If it drops more than 1ppm, it is time to slam. Refer to the OCLT test page for more detail perform-the-overnight-fc-chlorine-loss-test-oclt and to the SLAM page if you need to SLAM your pool slam-shock-level-and-maintain-shockingl

*** please note that I completely defer to chemgeek and others with more knowledge of the bromide issue - it may be that a high OCLT result could be due to the bromide, not organics - although it sounded like chemgeek said that the high FC loss due to bromide happens in sunlight - so, chemgeek, is the OCLT still valid with the bromide situation going on?? ***

 

[sbcpool]

Last night at 8:10 pm my FC was 4. Not a bad drop considering the UV levels.

That's about what I see on sunny days with my CA at 40. I have to add at least 32 oz. of 12.5% bleach each sunny day.

 

[Pogueld]

I would test your water mid day today without adding any chlorine and see how much can you lose. The key is to find the right amount to add at night so your FC never falls below the minimum.


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

 

[katwar]

Lisa, I actually posted all of my day losses in a post from yesterday. Bkfamily1 suggested I specifically see what my loss is overnight to determine whether I need to SLAM after my recent partial drain and refill. My losses during the day are pretty hefty. I am using the calculator to determine the amounts I need to add to keep my range from 5-7 based on a CYA of 60.

I would test your water mid day today without adding any chlorine and see how much can you lose. The key is to find the right amount to add at night so your FC never falls below the minimum.


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

 

[bkfamily1]

Kat,

That looks like good news to me.

First, let's talk why the numbers do not add up. I am thinking of three things that may be contributing to that.

First, the pool volume you are using may not be accurate. If the pool volume is a bit less than what you are using for calculating, it would explain why the FC goes up more than expected.

Second, it may be that the circulation takes a long time to even out the levels throughout the pool as you suggested. Waiting a bit longer after adding may be a good idea. But I would think we can trust the morning results after it has been circulating all night or any result that is obtained after a long time of circulation without adding anything. If you really want an idea of how quickly it is mixing, wait 30 minutes after the next time you add chlorine and collect samples from several places around the pool to see if they are the same. The fact that you collect samples from a consistent location is a good idea in any case. On a side note, I assume you are reaching down into the water and getting the sample from a foot or so below the surface.

Last, there may be some variation in your testing. If you want to see if that is the case, test the FC a few times from the same sample and see if you get the same results. If you do that, be sure to rinse the cylinder (and stir bar if you use one) well between tests. I also think it is a good idea before you do any test to rinse the cylinder with the sample water, dump it out, then fill to the line. Chemgeek can provide a more thorough answer, but I believe the two things that contribute to testing error the most are the consistency of filling to the same level in the cylinder and the speed of drop addition.

My gut feeling is that your volume is a bit less than the 23,000, but that just means you may need to adjust your math a bit. Over time, I am sure you will get a feel for that. As far as the change overnight, the difference between 8.5 and 9 is only 1 drop and within the normal error of the test method. So I would not really even think of those results as "different." So it looks to me like your OCLT is good and you do not have any meaningful organics or algae in play. So yes, for your CYA of 60, your target FC is 7 with a minimum of 5. And yes, I believe you are down to daily maintenance. It looks like the unusual drop in FC you have been seeing during the day is a combination of intense sunlight probably exacerbated by the bromide.

One other question - I assume you are testing your CC also? What has it been?

Oh, and you may want to ensure the refugee frogs are following the international rules of waste disposal when they are passing through your waters on their refugee rafts.