Hi all, I am a new pool owner (bought a house with a pool a few months ago), and I just had something really strange happen with my water chemistry that I can't explain. Maybe someone here can?
Disclaimer: All tests performed with a TF Pro kit unless noted otherwise.
The previous owners of my pool used mainly trichlor tablets, so my CYA was too high (~120). I removed the chlorine feeder and switched to LC only. I decided I wanted to do a salt conversion, and finally started work on it this weekend. I drained some water and refilled to lower CYA. After the partial drain and fill I had 7.5 FC, 0 CC, 7.6 pH, 80 TA, 350 CH, 80 CYA. Great, ready to add salt. Using a handheld salt tester, I determined I had around 400 PPM. Referencing a salt chart, I went to HD, bought water softener pellets, and added enough to the pool to get to around 3600 PPM. After letting it circulate my tester reported 3700, close enough.
The next day - today, I installed my SWG (Circupool RJ30+). Once everything was up and running, I did one more water test to get a baseline for future SWG power adjustment. But wait... no pink water after adding DPD powder? That can't be right? I pulled out a test strip and it too reported zero FC, as well as very low CYA (10-20). What?? I did a CYA test with the TF Pro and it reported 80 as expected. So both tests agree that there's no FC (down from 7.5 overnight?), but disagree on CYA. In the past, the strips and my TF Pro tests have agreed with each other pretty consistently, and this is the first time they are way off. I trust the TF test more, but I don't know how I lost all my FC in 24 hours with CYA at 80. I panicked and dumped a bunch of LC into the water.
I am in FL and the water is still chilly in the low 70's. I've never had a huge swing in FC like this before, and I'm struggling to explain it. The pool was unused between both tests and nothing out of the ordinary got into it, just a few leaves. The only change was the salt I added, but I'm not seeing anything that indicates adding salt affects FC. I also can't explain why my tests now disagree so much on my CYA level. I am choosing to believe the 80 result because that's what it was 24 hours ago, but I don't know how all my FC would have been burned up so quickly if that were true.
Anyone have an idea what might have happened?
Disclaimer: All tests performed with a TF Pro kit unless noted otherwise.
The previous owners of my pool used mainly trichlor tablets, so my CYA was too high (~120). I removed the chlorine feeder and switched to LC only. I decided I wanted to do a salt conversion, and finally started work on it this weekend. I drained some water and refilled to lower CYA. After the partial drain and fill I had 7.5 FC, 0 CC, 7.6 pH, 80 TA, 350 CH, 80 CYA. Great, ready to add salt. Using a handheld salt tester, I determined I had around 400 PPM. Referencing a salt chart, I went to HD, bought water softener pellets, and added enough to the pool to get to around 3600 PPM. After letting it circulate my tester reported 3700, close enough.
The next day - today, I installed my SWG (Circupool RJ30+). Once everything was up and running, I did one more water test to get a baseline for future SWG power adjustment. But wait... no pink water after adding DPD powder? That can't be right? I pulled out a test strip and it too reported zero FC, as well as very low CYA (10-20). What?? I did a CYA test with the TF Pro and it reported 80 as expected. So both tests agree that there's no FC (down from 7.5 overnight?), but disagree on CYA. In the past, the strips and my TF Pro tests have agreed with each other pretty consistently, and this is the first time they are way off. I trust the TF test more, but I don't know how I lost all my FC in 24 hours with CYA at 80. I panicked and dumped a bunch of LC into the water.
I am in FL and the water is still chilly in the low 70's. I've never had a huge swing in FC like this before, and I'm struggling to explain it. The pool was unused between both tests and nothing out of the ordinary got into it, just a few leaves. The only change was the salt I added, but I'm not seeing anything that indicates adding salt affects FC. I also can't explain why my tests now disagree so much on my CYA level. I am choosing to believe the 80 result because that's what it was 24 hours ago, but I don't know how all my FC would have been burned up so quickly if that were true.
Anyone have an idea what might have happened?
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