[delphinus]

I wonder if I have a bad Hanna tester. I can't for the life of me get consistent readings out of it. It seems like nobody else here in this thread has this problem?

For example I'll test my tank one night, get a reading of 0.18. The next night, I'll test again the next night and get 0.02. That seems ridiculous? Phosphate won't fluctuate that wildly will it? I think something's not right here.

I need to do like 10 tests in a row and see how badly it fluctuates .. but haven't had the patience to try it since you have to zero out between samples, and then of course do the read-timed for 3 minutes after zeroing. Mind you if I don't zero out the tester and just do a "read direct" on the same sample, I'll get the same reading. So maybe it's a reagents thing... some are reacting darker than others?

Although I tried one thing tonight .. I did a zero, then tried a read direct (without any reagent) .. expecting a zero reading. It came back under-range. I repeated this several times and each time it came back under-range. That seems wrong? Can someone try it on theirs and let me know if they get the same result, or if they get a legit 0.00 reading?

I first suspected the tester itself but I checked my water against another reefer near me who has the same unit, and we both got the same sort of fluctuating results. So I thought maybe my tester was OK after alll .. although I suppose the other possibility is we're both sitting on bad units.

I really would appreciate it if anyone has any thoughts or suggestions or have noticed any fluctuations in their day-to-day testing using the Hanna LR. Maybe PM me if it's uncool to hijack this thread.

PS. I don't even get a 0.00 reading on my RO/DI - I'm amazed that some of you are getting 0.00 in your tanks..