CYA is 0, what to do first?

[mailmanic]

We have a large in ground salt water pool, this is our third summer with it. First year we were constantly at the pool store, second year I found this forum and figured out our issue was mainly low CYA, and constant high consumption of our chlorine. Once we got CYA up to 70-80 and SLAMmed the pool we had a beautiful blue pool all season.
We just opened the pool and the first thing I tested was CYA and it's nearly 0 with no cloudiness at all in the test. My question is should I do any shocking while we work to bring stabilizer into the pool until CYA is 70-80 or would that be a waste. Should we test for anything else at this point or just focus on CYA before doing full tests.
Thanks!

 

[Mr Bruce]

Before you add any CYA you should make sure you can hold a little chlorine. Raise FC to 10, test in 15 minutes. If it is very low, keep repeating, bring to 10 until it holds FC>5 for an hour. Once it doesn't vanish right away you can start to add CYA and proceed as usual.

 

[Richard320]

Slow up a bit, Casey.

If you had CYA and now you don't, you might have ammonia. Under certain conditions CYA can break down to ammonia and ammonia takes huge amounts of chlorine to neutralize it.Enough some that sometimes water replacement is cheaper and faster. So first test for it. Add bleach to get to 10 FC and get it mixed good by brushing. Then retest it in 15 minutes. If you lost more than half the FC, you probably have ammonia. You probably also have 3 or 4 CC that you didn't have before. If this fits, stop and post about it.

If you didn't lose your FC so fast, then you can raise CYA and commence a SLAM. But only take CYA to 30 for now. That keeps shock level down at 12 FC. If you go all the way to 70 CYA, you'll need to go to 28 FC! Once it's all clear you can add the rest and get it to 70.

 

[mailmanic]

Ok, I went and bought some gallon jugs of 12.8% chlorine and added 2.5 gallons to our 35000gal pool per pool math app. We mixed and then tested and never got the chlorine reading to show anything above 1, nowhere near 10.
If it is ammonia present consuming the chlorine and converting our CYA, do we have to super slam the pool with lots of chlorine. Is there another way to test for ammonia present since our pool is on the large side. Thanks for your help!

 

[mailmanic]

Full tests kit results just for info:
PH 7.2
CH 125
TA 80
FC 0
CC 0
Salt 1800 (we have 9 40lb bags we'll be adding over the next week to get this up)

 

[Richard320]

Ok, I went and bought some gallon jugs of 12.8% chlorine and added 2.5 gallons to our 35000gal pool per pool math app. We mixed and then tested and never got the chlorine reading to show anything above 1, nowhere near 10.
If it is ammonia present consuming the chlorine and converting our CYA, do we have to super slam the pool with lots of chlorine. Is there another way to test for ammonia present since our pool is on the large side. Thanks for your help!

Yes. You can buy an ammonia test kit at a pet store that sells fish and fish tank supplies. Even Walmart might have it.

PS: If you buy a tester and it shows ammonia, it takes about ten times as much chlorine to get rid of it. SO if you shopw 3 ammonia, you'll need 30 FC just to get even, before you even start to work on any algae.