Zero CYA, Zero FC, High PH... visitors coming tomorrow... what to do?

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C

ChemSlayer

0
Apr 3, 2015
7
Naples, FL
A couple of readings from when I first got the house about a year ago:
2/22/14 PH 8+, TA 80, CH 360, CYA 60, FC 0
5/17/14 PH 8+, TA 70, CH 380, CYA 58, FC 0

I have been putting only liquid chlorine and muriatic acid. I have been struggling with the high PH. I have a spa spillover which I understand is contributing to the high PH. My FC does not seem to hold very long even with a decent CYA level, and it is often zero when I check.

Today, about a year later, I did a full reading and got:
PH 8+, TA 90, CH 220, CYA 0, FC 0

So what has happened to make my CYA disappear?

FYI: Yesterday for some reason I decided to shock the pool (8k gallons) with 0.75 lb. of potassium monopersulfate. I regret it and will not be using it again. I will be sticking with chlorine. Could that powder oxidizer have affected my readings?

I have a swarm of kids coming tomorrow for the weekend. How can I get the CYA up quickly for the chlorine to hold? The pool is in the hot SW FL sun.
 
Ah, I think I know. I had a repair done and the spa was drained along with about eight inches of the pool. But I still find it strange that it is zero. Something like 10-30 would make more sense. I am assuming I just need to add some cyanuric acid?
 
My first question is who is testing the water? Are you testing with a good test kit or is someone else testing?

You can definitely loose CYA over time. If you get enough rain, you will end up with overflow and that will dilute the CYA. I went from about 70 to less than 20 From Oct to March. We had a good bit of rain this year and there was a lot of overlfow from my pool.

CYA can also break down over a long period of time given the right conditions. If you were to check for ammonia, then that would indicate CYA breakdown.

Just add some CYA. Even though it takes a while to register on the test, it does react with the chlorine fairly quickly. Then maintain your FC relative to the CYA target you aimed for and you will be fine.

If you have a recommended test kit, I would say check for CC and also do an Overnight CHlorine Loss Test just to make sure something didnt start growing while your FC was zero.

Also a FYI. It is safe for anyone to swim with FC all the way up to the SLAM level.
 
What is Aflac? I am familiar with many terms but not that one.

I have been doing the testing myself using the K-2006 kit. I usually only do the FC and PH tests. The others once every few months. We do have heavy rainfall season here but I don't recall ever experiencing overflow. I guess the water is evaporating as well, especially from the hot spa. I don't think I can do the CC test since it will pick up the potassium monopersulfate I just put in and I don't have the special neutralizing reagent. The overnight test is a good idea.
 
My cya drops quite a bit over the year. Especially when it is rainy. Couple that with draining the spa and isn't that surprising. Yes, just add more. I have to add every year.
 
Your situation is one of the rare ones where I would suggest using dichlor "shock powder." There are three varieties of powdered chlorine sold as "shock," so do read the label. Not knowing the size of your pool, I can't tell you how much each one pound bag will affect things, but pool math can. Plug your volume in, and your current readings, and then scroll down to effects of adding chemicals. It will tell you how much each pound will change FC, CYA, and pH.
 
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