White Flakes from SWCG when changing polarity

[english72]

I installed a Circupool Universal 55 back in May 2024. Ever since I changed the output to 90% the SWCG deposits white flakes through the return jets when it changes polarity which is about every 8 hours.
Here are my numbers based on the TFT-100 kit:
FC = 7.0
pH = 7.6
TA = 75
CH = 380
CYA = 70
Salt = 3800
Borates = 50
Water Temp = 80F
CSI = -0.30
We are on city water which I measured pH = 7.8 and TA = 70

I run the pump and SWCG for 8 hours since we have higher electric rates. Run from 4AM to noon, lowest rates. I run the pump at 1500 RPM.

I scooped up some flakes from the bottom of the pool today and added Muriatic Acid to them. When I did this they changed from white to clear but did not dissolve. I attached a picture.

When I purchased the bypass kit for the SWCG it came with a Phosphate test and I measured this morning which came out to 3000 ppb.

 

[chlorinatorpro]

This was previous thread that helped me out several years ago but unfortunately, I could never determine the source.

White Flakes - Not Calcium

Was at a customer's pool. He thought he was not getting chlorine production from the T-15 cell that he had for 2 1/2 months. There was a thick layer of white flakes that didn't look like calcium and his AquaRite readings were within normal ranges. He was "sure" that his pool water had no issues...

www.troublefreepool.com

 

[Uhhello]

I would get the same despite trying to keep CSI down as much as possible. I drained and refilled with our water softener plumbed in. Have had new cell on for 1.5 seasons now and haven't had a fleck of scale on the cell since re-filling.

 

[english72]

I haven't used any dry acid only Muriatic Acid. I wonder if it could be the phosphates causing the issue. Maybe I'll try phosphate remover since it is relatively high. Thanks for the link.

 

[english72]

I may have found the culprit, I used chloring pucks early in winter/spring to raise my chlorine and CYA. I used looked at the pucks that I used, Clorox XtraBlue+ and it says that it contains 0.99% of copper sulfate. I will wait until Fall to remove/refill the water out of the pool.

XtraBlue+™ Chlorinating Tablets | Chlorine + Sanitizers | Clorox® Pool&Spa™

Clorox® Pool&Spa™ XtraBlue+™ Chlorinating Tablets kill bacteria and stop all types of pool algae.

www.cloroxpool.com