Disappearing CYA

[vinnygnj]

I tried posting this over at TFP but I keep getting an error so ...

I'm having a problem with no CYA in the pool along with algea which I believe is due to no CYA. I opened the pool to 0 CYA and used trichlor to get the CYA to 35. I hadn't tested the CYA all season as in past seasons it usually is the same.

I have been having an algea problem for the past few weeks and haven't been able to solve it. I have been home the past few days and have been concentrating on solving the algea. I've been putting chlorine in and checking every few hours and it reads 0, I assumed it was being eaten by whatever in the pool. On a whim today I tested the CYA and found it to be 0.

I haven't drained the pool and whatever rain we had didn't cause the pool to overflow a lot (AG pool) so I am at a loss. I did put some stain remover in that seemed to be acid based and it had me drop the PH to 7 (I might have gone lower). I will be adding CYA to the pool but I am wondering on what's going on?

Any feedback on this is appreciated!

Thanks!!

Vinny

[aylad]

There has been some discussion in the past on this forum about the ability of an extended algae outbreak to break down the CYA. I think chemgeek or waterbear put a detailed explanation of why this happens somewhere, but in layman's terms, your algae bloom has probably degraded your CYA to zero. Given this condition, you're going to lose as much chlorine to the sun as to the algae, so you're fighting a losing (and expensive) battle. I would add enough CYA in one dose (it'll take weeks if you just use trichlor) to get your pool up to about 20 ppm, and in the meantime raise your chlorine to shock level and keep it there by testing and adding more every few hours like you've been doing. Keep in mind that your chlorine is going to be much more effective if you'll add it at night because the sun's not consuming it, and that it'll take a week or so for your CYA to completely dissolve, so you're going to have to be pretty consistent with your testing and bleach additions to clear up the bloom.

Janet

[vinnygnj]

Thanks!

I went and bought stabilizer, added it to hot water and added it to the pool. I also have put in trichlor pucks and will monitor the pool as much as possible.

I will continue to add beach and keep the chlorine at high levels.

[aylad]

I also have put in trichlor pucks and will monitor the pool as much as possible.

Keep an eye on your pH, especially if you started at 7.....the trichlor is going to drive it further down.

Janet

[vinnygnj]

Janet,

Thanks for the reminder!

There was some mis-communication on my part ... I dropped the PH to 7 for the stain remover and then brought it back up 24 hours later to 7.6 and hopefully locked it in with baking soda so it should stay for a while.

Thanks again!

Vinny

[chemicalbalance]

Trichlor is the wrong product for this problem.

Go to Sams Club and buy the big three pack cases of 1.5 gallon jugs Clorox.

In Western PA they cost $7.50 per case.

SHOCK YOUR POOL WITH CHLORINE BLEACH UP TO ABOUT 15 ppm at night.

Do this a couple of nights in a row. I have an inground pool and had the same problem you are experiencing with CYA loss.

It took me about 50 gallons of bleach over a two week period to fix it. This problem stems from not consistently maintaining an appropriate chlorine level.

You simply have to burn the ammonia out of the pool. It will take time but your pool will come around. I would not add any CYA till you get the chlorine level consistently stablized.

Also, all this bleach is going to send your alkalinity through the roof. You should aerate during the entire process to keep your water churning.