Pool store water testing vs Taylor kit / sediment on bottom


New member
Jun 23, 2019
Cambridge, Ontario
Just wondering how reliable are the pool store water tests. When I opened the pool this season, I only had enough regent for two CYA tests. The first read 0 and so I added granular stabilizer according to calculator to get it to 50-60. I retested next day and thought I recorded 60 cya. Few days later I took my water to the pool store and get their numbers and cya shows at 29. Few days after that I took another sample to another store and got same number 29. Backwashed once between these tests. Pool is 26000 gallon IG vinyl, sand filter. Not sure which number to use while I wait for Amazon to deliver new regents.

My other issue after slamming the pool, the water is clear but now I have powder that settles at the bottom of the pool only and the filter doesn't catch it when vacummed. When I brush, I can see the white stir up and clouds the water. When it settles it's got a light brown tint to it. More visible where it collects at the liner seams and it sort of etches patterns on the bottom as well. Could this still be algae? I have zero cc every test and .5 or less OCLT. I been keeping it at SLAM levels for last 1-2 weeks (based on 30 cya) before that used the 60 cya levels. Aside from vacumming to waste any other way I can try and catch this sediment into the filter (de?)


Gold Supporter
Bronze Supporter
Jun 11, 2018
Verona, MO
Don’t trust pool store rests, get a reagent refill.

If you would, add your pool information to your signature to help the experts. something similar to mine. Settings/signature

I have used DE in my sand filter it should help. Sand filters are much slower filtering fines than cartridge type. If you can swing the $ get a robot. We love ours, makes pool care much simpler