CYA went up?

LordDunlow

Active member
May 31, 2017
29
Melbourne, FL
We just got a ton of rain from the remnants of Harvey and I had to drain a bunch of water to keep the level in my inground fiberglass pool below the top of the skimmers last night. I cleaned the pool this morning and let everything circulate for a few hours and then decided to test all the chemicals with the TF 100 kit. Calcium hardness just dropped a little, TA stayed roughly the same. Chlorine and pH weren't off much either (pool is SWCG). However, my CYA was up to 90. Last I checked before the rain(could of weeks ago was 70. Can rain make CYA go up or is there anything that can throw this test off? It normally isn't a very cloudy solution, but this one was today.
 

Oly

Gold Supporter
Jun 28, 2017
1,552
Fresno, CA
Test it again after a bit. The CYA test is interesting in that it does not have an end point or change colors like the titration or color-metric tests. It is important to use the same methodology every time with this test as slight variation does change the results. I cannot imagine how in your situation the CYA increased 20ppm and I would have expected it to drop some. Did you use any Trichlor pucks or shock? Not sure if there are other contaminants that can alter the test results.....chemtrails????? just kidding I think. :D
 

LordDunlow

Active member
May 31, 2017
29
Melbourne, FL
Test it again after a bit. The CYA test is interesting in that it does not have an end point or change colors like the titration or color-metric tests. It is important to use the same methodology every time with this test as slight variation does change the results. I cannot imagine how in your situation the CYA increased 20ppm and I would have expected it to drop some. Did you use any Trichlor pucks or shock? Not sure if there are other contaminants that can alter the test results.....chemtrails????? just kidding I think. :D
Definitely no trichlor/pucks. Nothing has been added other than rain water from the sky and chlorine generated from the cell.

It was odd in that I could see precipitate in the solution in the first few drops into the CYA vial.

I'll probably retest later this weekend.