I think I may be doing something wrong with this test. Just how obscured is the black dot supposed to be? Completely? I’m testing my CYA at 80 and my pool builder tested it at 100 with their “disc” test. I really don’t know how this is possible, I don’t use pucks and have had to drain 6-8 inches of water from a 7800 gallon pool because of rain over the past two weeks (then add some fresh back after evaporation). I know I shouldn’t trust their tests, but I’ve always been unsure of that particular result- it seems subject to interpretation.
TF Pro CYA test
- Thread starter phrantic09
- Start date
His test is +/- 25%.
So an 80 will read 60 to 100 as acceptable. If the calibration is off there is no telling how off it may be.
DrewLG
Gold Supporter
- May 31, 2022
- 677
- Pool Size
- 8000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-20
Calibrating your eye against a known reference will help a lot.
Buy this 50ppm CYA standard solution: R-7065 CYA Standard 50ppm (2oz) and perform the CYA test by mixing CYA reagent with the solution instead of with pool water:
Shake, wait a couple minutes, shake again, and fill the viewing tube to the 50ppm line. Under the lighting conditions you'll normally be using, look down into the tube. What you'll see is the endpoint that you should look for when you do the test with your pool water.
Also see what the dot looks like at 70, 60, and 40 ppm, so you'll have an idea of how much visible difference there is between the measurements.