Scaling Above Waterline - Help

rockylreed

Member
May 15, 2019
6
Lexington, SC 29072
I recently installed a Hayward T-15 SWG and have 3900 ppm salt. Pool is gunite and over 10 years old. I increased calcium hardness from 225 to 350ppm. CYA is very high due to previous home owner at 150, so I am keeping my chlorine at 7 to 9 ppm. Ph is kept between 7.2 and 7.5 with an alkalinity of 110. After swimming and splashing in the pool today, I see a white haze on my tile above the waterline that appears to go away when wet but drys white. What is this? How can I get rid of it?
 

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mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
22,036
Laughlin, NV
Welcome to the forum!
How are you getting your test results?
Try some 4:1 dilute muriatic acid. It looks like scale, but your water data does not imply that should be happening. Though you will get some evaporation scaling at the water line. Odd that it is that far above the waterline.
I suggest you read ABC's of Pool Water Chemistry and consider reviewing the entire Pool School eBook.
 

rockylreed

Member
May 15, 2019
6
Lexington, SC 29072
Welcome to the forum!
How are you getting your test results?
Try some 4:1 dilute muriatic acid. It looks like scale, but your water data does not imply that should be happening. Though you will get some evaporation scaling at the water line. Odd that it is that far above the waterline.
I suggest you read ABC's of Pool Water Chemistry and consider reviewing the entire Pool School eBook.
I have a TF-100 kit and have also verified my results with the local pool store. The only result on my last pool store double check that doesn’t match my number is alkalinity. They measured 60 and I’m measuring 110. Even with this difference, I don’t understand why I would see scaling above the waterline only. Also, my salt cell is creeping up 100ppm every week without adding in salt and with the same water level.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
22,036
Laughlin, NV
I would not bother with pool store tests. Just confuse you.
They gave you adjusted alkalinity. Our Poolmath manages that when using the TA for chemical additions.

Salt cell ppm is not very accurate. I suspect that is the water getting warmer and the cell salinity adjustment not being very accurate. As long as the cell is making chlorine, ignore it.
 

rockylreed

Member
May 15, 2019
6
Lexington, SC 29072
I would not bother with pool store tests. Just confuse you.
They gave you adjusted alkalinity. Our Poolmath manages that when using the TA for chemical additions.

Salt cell ppm is not very accurate. I suspect that is the water getting warmer and the cell salinity adjustment not being very accurate. As long as the cell is making chlorine, ignore it.
I’m going to drain 50% of my water after July 4th to start over so that I can get CYA back to where it should be at 80ppm. I’m using pool math’s suggestions to manage and add chemicals.

After diluting the acid in a 5 gallon bucket, can I use a pool brush to clean up the tile? The tile just has a haze to it - it doesn’t have a thickness not even a film.

Another question, what can I buy to test Ph more acutely? What would you recommend for salt testing other than strips? The TF-100 only has the daily reference test when you also get the reference chlorine.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
22,036
Laughlin, NV
The best pH test is what comes in the TF100 kit. If you have issues matching colors, try using 4 drops of reagent.

I would not mix up that much dilute acid, but up to you. Use a brush to put it on. Use proper PPE. Have a hose ready to wash it off.