CYA creeping up when only using bleach

[DesertSwim]

Honestly, I've pretty much ignored my pool over the winter, dumping bleach into now and then. After we refilled our pool last summer the CYA was about 60. I've only used bleach since then. Today I tested it and it was at 100. How does that happen if I'm not using tabs or shock? I'm discouraged now.

And just for reference the other levels I tested were:
FC - 6
TA - 150
pH - 8+

[CarlD]

The first thing I can think of is you are testing your water incorrectly or using old reagent. Are you using strips or the proper black-dot test?
Isocyanuric acid can only be added by using Tri-chlor tabs, Di-chlor tabs or powder, or powdered CYA. It cannot be increased by adding bleach.
So either your testing has a problem or one of those chems was added inadvertently.

[SafetyBob]

Carl, I don't know if I am wasting money or not, but I have started replacing all my chemicals on my Taylor 2006C test kit for just the reasons you point out above. I don't have a lab here at the house to test my supplies to ensure they will give me accurate results. Since it is not "that" much to do it, I replaced them all. Testing accurately did so much to enhance my pool experience last year, I cannot feel good about operating the pool unless I KNOW my chemistry is fresh and right on.

Bob E.

[CarlD]

Sounds like a plan!

[waterbear]

You can also buy standard solutions from Taylor to verify your testing results and reagents. If you are getting that much discrepancy in the CYHa test you might want to invest in a bottle of CYA standard solution.