I've been bringing my CYA level up A couple days ago I was about under 40 so I added some CYA today I was at about 35 we did have a little rain. So my R-0013 was empty so I opened a new one maybe a year old, did another test reads “0” CYA. I did about 3 tests still “0”. I did have some old test strips it they show CYA but low. There no way it can be “0” you think the R-0013 is bad? That’s all can think of .