CYA at 0 after AA treatment?

[ajcannon]

Hey everyone. I’m located in Florence, SC and I have a 25,000 gallon in ground vinyl saltwater pool. The water is perfectly clear and my SWCG is generating chlorine, but after a recent (one week ago) Ascorbic Acid treatment to remove some iron stains caused by my fill water I am having a few issues. I use a Taylor K-2006 test kit. First, my chlorine is staying at or near 0 since the treatment even with increasing the power and time that my SWCG is running. Second, my CYA levels are now reading as 0ppm.



A little backstory - I had a horrible time last year and ended up realizing that my CYA level was somewhere in the high hundreds (800 or so?) after using pucks exclusively for years. With multiple partial drains and refills I got my CYA levels down to 50ppm and left it there. I have not tested CYA since closing down the pool last winter.



So…I’ve been testing chlorine every morning and I am averaging about 3.5ppm chlorine in the mornings but 0 to 0.5 in the afternoons. My SWCG is running 24/7 right now which is why I suspect I’m not having algae problems. I know that AA treatment will sort of “eat” the chlorine but I’m beginning to suspect that my actual problem is that my cya level is 0. My question is - how would it have gotten so low? I haven’t added a lot of water (a few inches total) since last October.



Does AA eat away at CYA too by chance? Is there a chance that my CYA reagent is bad? I’m hesitant to go buy a new bottle because I did that last year after testing so often while doing the drain and fills on my pool. Or is my CYA actually 0? I had some leftover test strips which I know are not reliable but they confirm the 0 CYA reading?



I guess my main question is, will the AA treatment mess up my CYA readings or am I safe to go ahead and start adding CYA back into the pool?



If I should add CYA back in, what is the best method? Go back to using pucks for a little while? Add stabilizer powder? If powder is OK, can I use the Clorox Stabilizer powder found at Walmart?



Thanks for the help!

 

[ajw22]

CYA degrades while the pool is closed and it is not unusual for CYA to be zero at opening.

But let’s make sure your water can hold chlorine before you add CYA.

Add 10 ppm of liquid chlorine and then test your FC in 30 minutes. If you have 3 ppm of FC or more then you are good to add CYA. If your FC is less post back here and we will discuss.

 

[ajcannon]

CYA degrades while the pool is closed and it is not unusual for CYA to be zero at opening.

But let’s make sure your water can hold chlorine before you add CYA.

Add 10 ppm of liquid chlorine and then test your FC in 30 minutes. If you have 3 ppm of FC or more then you are good to add CYA. If your FC is less post back here and we will discuss.

Thank you. I just added the liquid chlorine and will report back here in 30 minutes or so. Thanks for your help!

 

[ajcannon]

Thank you. I just added the liquid chlorine and will report back here in 30 minutes or so. Thanks for your help!

Ok, great news. I added 10ppm liquid chlorine and tested 30 minutes later and it measured 9.5ppm. That makes sense to me because the chlorine I was using was a little on the old side so it probably wasn’t a true 10ppm that I added.

So my next step is to add stabilizer. What’s the best way to do that? Pucks or powder? (I’d prefer powder if either works.) Can I use the Clorox stabilizer powder or should I go with another brand? Thanks again!

 

[ajw22]

Dry stabilizer adding using the sock method. Clorox stabilizer powder is ok.

 

[ajcannon]

Dry stabilizer adding using the sock method. Clorox stabilizer powder is ok.

Thank you so much!