Disappearing CYA

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

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

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.

Quote:

---

Originally Posted by vinnygnj

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

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

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.

THis happened to me at the beginning of this swim season. I opened to a swamp, and got the water cleared up pretty quickly with bleach, but had an awful time holding the chlorine overnight. I put in stablalizer, to get it up to 30, and kept adding bleach to take it back to shock levels everytime I could test. It took a good 2 - to 2 1/2 weeks for it to hold chlorine overnight. I don't even know how many gallons of bleach I used:D Even though the water looked crystal clear, and there showed no cc, it still needed lots of bleach to get the water to hold the chlorine overnight. My water has been fine since:cool:

Quote:

---

Originally Posted by 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.

---

I disagree. Without CYA in the water, then most if not all the bleach she adds during the day will be lost to sunlight. I stand by my advice to go ahead and add the stabilizer since it takes a little time to completely dissolve. The poster has already stated that she is keeping her chlorine levels high usng bleach during this process, so delaying the addition of CYA makes no sense. Also, adding bleach to a pool does not necessarily raise total alk, and even if it did, aeration is not going to lower it. Acid lowers the alk, aeration raises the pH without an accompanying increase in alk.

Janet

It seems that the chlorine is being maintained. I put bleach in this morning and went out for the day. I came home and after a day of some sun (I think) and rain it was well over 5 (based on the color) using a Taylor K-2005 kit.

I left it to see if in the morning it is above 5 or not. If it is I will dilute the amount to get a more accurate reading if not in goes more bleach.

My PH took a dive yesterday after adding the stabilizer and at this point it's at 7.4, so hopefully I'll be in the clear and things will start working the way they used to!

I do have a question though about the amonia - chlorine and amonia are supposed to combine for CC - I never got CC in my pool. I would imagine that after a night of killing and combining with amonia that the CC would be through the roof in the morning - I don't think my pool had a lot of amonia in it.

Thanks!

Vinny

BTW, I am a he, not a she ... how many Italians named Vinny do you know are shes? ;) LOL!!!!

I think the problem is solved!

After testing the water this morning, the chlorine was at around 5, I added some more bleach and in the NJ hazy sunlight the chlorine level was still above 5.

I only added 4 lbs of stabilizer and by my calculations (13, 000 gallons) it should only be at about 30 to 35 (unfortunately the store ran out of testing reagent) if it's all disolved. I would imagine at the rate I was losing chlorine before adding the stabilizer that the chlorine is going towards killing the algea now, if any is alive. I did add some more bleach to give the existing chlorine a boost. Hopefully my pool will go back to normal.

Thanks for the help!

Vinny