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Thread: Is it OK to use liquid bleach and chlorine tabs until I can get my CYA issue solved?

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    Is it normal for a CYA level to rise from around 40 to 95+ in a month's time??

    Hello. I tested my CYA a month ago and it was around 40. I then remeasured it this week (a month later) and it jumped to 95+. To make sure, I brought water to the pool store and they also tested it at 95+.

    Is it normal for the CYA to jump so much in a month? What could be going on? All of the other readings are normal, although in the past week, the FC level dropped to nearly zero, then I shocked the pool and got the FC to rise, but then it seems to have dropped to around 2.0 again.

    Prior to this I have never had an issues with keeping FC stable. I am using the cholorine tabs in the chlorinator. Also, it has been crazy hot in Connecticut (90*+) for a few weeks with no rain.

    Any thoughts?? Thanks!!
    32,500 gallon in ground Gunite/White Plaster, Pentair Cartridge Filter, Pentair Propane Heater, Pentair Racer robot cleaner

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    Re: Is it normal for a CYA level to rise from around 40 to 95+ in a month's time??

    Chlorine tabs certainly add CYA. Your "shock" may have added a lot. Enough ot account for 50+ in a month? Sure, if you used a lot of those two products.

    Please read "The ABC's of Pool Water Chemistry" up in Pool School for more insight on this.
    Dave S.
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    Can you drain and refill a pool slowly (2 inches at a time) to reduce CYA?

    Hi. My CYA is 95+. Is it possible for me to drain off, say, 2 inches of water at a time and refill it, daily over the course of 10 days to try to reduce the CYA level?

    I am bad at math, but for a 32,500 gallon pool, how many gallons of water are in 2 inches (pool is 20x40)? That might give me a sense of how long it will take me to "change out" maybe half of the total water.

    Thanks
    32,500 gallon in ground Gunite/White Plaster, Pentair Cartridge Filter, Pentair Propane Heater, Pentair Racer robot cleaner

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    Re: Can you drain and refill a pool slowly (2 inches at a time) to reduce CYA?

    The estimator at the bottom of the Pool Math page says that 20X40X1 is 6000 gals so 2" would be 1000 gals
    Bob - Palm Beach by San Juan Pools. approx 5000 gals., Pentair 320 cartridge filter (all new guts installed by me), Goldline SWG, 'New to me' Kreepy Krauly Sand Shark, Intermec 104 Timer Test kit: TF-100 w/Speed Stir

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    Re: Can you drain and refill a pool slowly (2 inches at a time) to reduce CYA?

    What you could do is drain to right around the bottom of the skimmer so you are not sucking air into the system. Then mark with a pencil or blue tape to about 75% of the skimmer, then fill up to the mark and check the time. Then go back and see how many gallons are filled up per minute and base your calculations on this method.

    Regarding 2" at a time, that is fine, although this will take you quite a bit of time. Considering you have a plaster pool, you could actually go lower and fill up with water. I probably would dump 2' at a time and then fill, mix for a few hours and test for CYA. you can then gauge how much of a drop you have in CYA based on water replacement. Repeat the cycle until you are down to around 60-70 (which is still manageable). You will loose some CYA over the next few months and then your levels will be perfect for next year.
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    Re: Can you drain and refill a pool slowly (2 inches at a time) to reduce CYA?

    At 2" that's only like 3%. But it's a diminishing value. So each time you do it you will have a smaller and smaller effect on the total CYA. That's why it's recommended to do the drain and fill as large of an amount as is safe for your ground water situation.
    Bob - Palm Beach by San Juan Pools. approx 5000 gals., Pentair 320 cartridge filter (all new guts installed by me), Goldline SWG, 'New to me' Kreepy Krauly Sand Shark, Intermec 104 Timer Test kit: TF-100 w/Speed Stir

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    Re: Can you drain and refill a pool slowly (2 inches at a time) to reduce CYA?

    Why only 2 inches? That's about a 1,000 gallons. I'm guessing it would take 30 or 40 days to get the CYA down 50%.
    16' x 34' vinyl in ground - 16,500 gal.
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    Re: Can you drain and refill a pool slowly (2 inches at a time) to reduce CYA?

    Quote Originally Posted by Mike1162 View Post
    Why only 2 inches? That's about a 1,000 gallons. I'm guessing it would take 30 or 40 days to get the CYA down 50%.
    I have a well and am afraid of burning it out/running it dry if i drain 2 feet from the pool and have to run a hose to fill the pool for a few days straight.
    32,500 gallon in ground Gunite/White Plaster, Pentair Cartridge Filter, Pentair Propane Heater, Pentair Racer robot cleaner

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    Is it OK to use liquid bleach and chlorine tabs until I can get my CYA issue solved?

    Hi. My CYA is 95+. I believe that I need to keep adding more and more chlorine to be effective given the high CYA level.

    Since my chlorine seems to burn off quickly due to the CYA level, is it OK to continue to use the chlorine tabs (to keep a constant flow of chlorine in the water) AND also use liquid bleach to keep the levels high? The only reason I would use the tab is to ensure that at least some chlorine is constantly getting put in the water, since I am not sure how quickly the chlorine burns off.

    I wouldn't think that pouring liquid bleach in the pool which would then get circulated through the clorinator would cause any issues, but I am not sure.

    I was hoping to use this method until I can figure out how to drain the pool, etc.


    Thanks
    32,500 gallon in ground Gunite/White Plaster, Pentair Cartridge Filter, Pentair Propane Heater, Pentair Racer robot cleaner

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    Re: Is it OK to use liquid bleach and chlorine tabs until I can get my CYA issue solv

    We would recommend only using liquid chlorine/bleach at this point. The tabs will just continue your CYA rise. With high CYA, your UV burnoff should be less than or equal to the normal pool at the proper ratios. The downside is the high target FC; see this Pool School - Chlorine / CYA Chart, and the fact if you suspect algae and need to SLAM the FC levels are very high.

    As to your CYA reading, how did you reach that result?
    16' x 32' (21100 gal), vinyl, 1.5 hp Hayward SuperPump,
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    Re: Is it OK to use liquid bleach and chlorine tabs until I can get my CYA issue solv

    I'm not a mod, but you can keep everything in the same thread.

    If I were you I'd pull those tabs immediately, all they are going to do is raise your CYA even more!

    There is no problem using just bleach, lots of us do that every day.
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    Re: Can you drain and refill a pool slowly (2 inches at a time) to reduce CYA?

    Quote Originally Posted by Clyde View Post
    I have a well and am afraid of burning it out/running it dry if i drain 2 feet from the pool and have to run a hose to fill the pool for a few days straight.
    Best to keep your questions in one thread.

    Draining only two inches would waste a lot of water and is very insufficient at lowering your CYA. Best to drain as much as possible in the fewest steps.

    You need to take the pucks out and just use bleach. The pucks will only increase your CYA. If you are having trouble holding chlorine, you should do an OCLT Pool School - Perform the Overnight FC Loss Test (OCLT). If you fail the OCLT and you will need to SLAM. SLAMing with a CYA of 95+ would be difficult and expensive. You would definitely need to drain to complete the SLAM.

    Let us know if you have any questions on performing the OCLT. For now, keep your FC at 12 using plain bleach.
    Karen
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    Re: Is it OK to use liquid bleach and chlorine tabs until I can get my CYA issue solv

    Quote Originally Posted by Clyde View Post
    Hi. My CYA is 95+. I believe that I need to keep adding more and more chlorine to be effective given the high CYA level.

    Since my chlorine seems to burn off quickly due to the CYA level, is it OK to continue to use the chlorine tabs (to keep a constant flow of chlorine in the water) AND also use liquid bleach to keep the levels high? The only reason I would use the tab is to ensure that at least some chlorine is constantly getting put in the water, since I am not sure how quickly the chlorine burns off.

    I wouldn't think that pouring liquid bleach in the pool which would then get circulated through the clorinator would cause any issues, but I am not sure.

    I was hoping to use this method until I can figure out how to drain the pool, etc.


    Thanks
    You seem to have a fundamental misunderstanding about several things.

    High CYA means you use LESS chlorine daily, not more.

    CYA protects your chlorine from "burning off" from sunlight.

    The tabs are what is adding the CYA, so you need to stop using them completely.
    TFP Moderator
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    Re: Is it OK to use liquid bleach and chlorine tabs until I can get my CYA issue solv

    Just keep in mind that because of the high CYA, a lot of the chlorine in your pool is being rendered inactive. In order to keep the pool sanitary, you then have to put more chlorine in than is being buffered by the CYA. That's where the numbers on the Chlorine/CYA Chart come from. They take into account the amount of chlorine that is registering on your test but is not actively sanitizing your pool and adjust for that fact.
    26k Gal IG vinyl, Hayward Super 1HP, Hayward Pro Series S244T Sand Filter, TFTestkits TF-100 w/ Speedstir
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