CYA slowly creeping up but I have a SWG

[LearningAboutPools]

I never use shock or add anything to my pool but muriatic acid.

I have used small amounts of Jacks Magic Purple Stuff. However, this season my CYA creeped up from 50 or 60 to 90.

What am I missing??

Does muriatic acid somehow cause CYA levels to increase?

Maybe my Taylor test kit has gone bad somehow??

 

[dfwnoob]

Only CYA (or chlorine stabilized WITH CYA) causes CYA to increase, and that's a huge jump. Assuming the CYA fairies didn't come by and dump stuff in your pool, I'd suspect two things:

1. Are you sure your initial testing was accurate?

and

2. Are you sure your reagents are good?

If you don't already have some, I'd pick up some 50ppm CYA Standard Solution and make sure your testing method is actually working correctly. TFTestKits has 2oz bottles of the R-7065 solution for $6.50.

 

[LearningAboutPools]

I didn't know that existed that's perfect thanks!!