Well may need to work in my precision testing skills just a touch. I learned from having the calcium checker that these things can be super finicky. I was never able to get anywhere near consistent back to back readings with the calcium checker so ended up selling it and sticking with Salifert.
Forgot to mention I do a couple extra things mentioned in the last couple posts with some slight differences. The Hanna vials gets rinsed with tank water before use if I remember, but I feel this is a bit of a waste of time seeing as how they get rinsed with RODI before being put away. Definitely in between test if done at the same time to double check. I also make sure there are no finger prints by giving it a good polish with the inside of my t-shirt usually and check for fibres on the outside. I give the vial a good shake for 1 minute until all crystals are dissolved, and yes it creates air bubbles, but to remedy this I spin the vial horizontally and allow the big bubble inside to dissipate the micro bubbles. If there's some micro bubbles stuck, it gets a tap on the counter and some more rolling. Until they're all gone.
And with the regent pack it gets shaken and flicked a bunch of times while holding one corner upwards, 2 sides cut along the dotted line and the open the flap by pressing inwards from the sides and at no point are there any fingers or anything touching the inside silver lining of the packet. Then a vee shape is formed, powder is dumped, pack is flicked until there no more powder left. Well there's a bit of powder residue left but that near impossible to remove. It's consistent anyway
Potatohead & Mindy: May put a microfibre towel with the checkers from now on, good idea.
Mindy: Not sure about drying the vial inside with paper towel before testing, i'd wonder about getting fibres left behind in the vial? Good call on leaving the vial out for the 3 minutes countdown to give it one more shake, will try this. Do you think rinsing it with hot water makes any difference? I just use cold usually
And at the end of the day I'm not expecting exact back to back numbers, the 8 percent difference last night is fine with me. Just trying to get in the low range to help combat tiny bits of algae that wil never completely go away. Would love to see anything below ten ppb right now, which is what the Salifert is always giving the result for...
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