My CYA test never gets to the point that I can not see the black dot. It (the test kit) is only a year old and I was successful in testing it last year. What gives?
I assumed the CYA was too high so I drained and filled. No change. Tested my tap water. Black dot all day long.
I assumed the CYA was too high so I drained and filled. No change. Tested my tap water. Black dot all day long.