New Pool owner - Chemistry Help - Cloudy Water

[fziffel]

I bought a new home with a 16x32 IG pool. Closed it last fall with phone help from previous owner. Opened O.K. & initial pool store tests consistently showed low CH (130), hi CYA (100), lo TA (70), & hi Pho (300). Water was crystal clear up to fathers day when it had it's 1st heavy use of the year. Next morning pump pressure went from it's normal of 17 psi to 25psi with lo flow from jets & cloudy water.

Backflush of sand filter provided a little temporary relief, but soon back to 25psi. If I put multiport to "circulate" bypassing the pump. pressure & flow return to normal.

Discovered this site & yesterday performed deep clean of filter which had 2" of scum (a lot of cotton wood) on top. Now pressure is back to 16 - 17psi & flow is strong.

Here are my latest test results, taken yesterday before deep clean of filter.

FC - 0
TC - 0
CH - 140
CYA - 99
TA - 90
PH - 7.4
PHo - 300

I read here that using tabs in auto chlorinator raises CYA.

What should I do next?

 

[Texas Splash]

Hello and welcome to TFP! Well, this first piece of advice might seem disappointing, but you're not alone - myself included when I started. Your test results are from the pool store correct? Well, they won't help you I'm afraid. They are usually incorrect. Yep, with all the computer gadgets and stuff they have, their testing is very unreliable. Your #1 course of action should be to get your own "proper" test kit - either a TF-100 or Taylor K-2006C (link below). You will not look back once you see how easy it is to test your own water and do so reliably.

Now if your CYA is indeed at 100 (or perhaps much higher), the only way to lower CYA is a water exchange. The CYA got that high from weeks/months of pool store products like tabs, bags of shock, etc. But once you get that CYA down to where it needs to be, chlorination will be easier to manage and the CYA will never rise again unless YOU want it to.

So those are your first two real chores at the moment - getting one of those proper test kits (I recommend the TF-100) and preparing for a water exchange to lower CYA. You can wait for the test kit if you want before trying the water exchange. Just don't place your trust in the pool store testing.

Let us know if you have any more questions. We look forward to hearing back from you. Nice to have you with us.

 

[fziffel]

TF-100 test kit already ordered!

Water exchange sounds daunting. Is there a calculation that tells me how much to drain? Does my tap water contain CYA?

I do have wrinkles in liner and draining would allow me to possibly correct them.

 

[Mr Bruce]

Let's pretend those numbers are right. In that case you would want at least a 50% replacement to get to 50 CYA. If you had to do it in stages that would be ok too, just take a little longer.

There is no CYA in tap water.

 

[Texas Splash]

Tap water won't have CYA. CYA (stabilizer) comes from additives in things like chlorine tablets, bags of shock, etc. When it comes to lowering CYA, you could use the Poolmath Calculator (link below) to help tell you how much to lower from say a CYA of 120 to 40 for example. But I would caution you that the pool store CYA test was probably not correct. If you wanted to get a jump on things though and believe that your CYA is at least 100, then a 50% water exchange should lower CYA by 50%. I keep my math easy. You can lower more if you wish to address some liner issues, but we generally advise to not lower more than 12" to the bottom or no lower than the lowest step to retain structural support of the pool shell in the ground.

Glad to see you ordered the TF-100. You'll be impressed.