Hanna InstrumentsHanna Marine Magnesium Checker HC HI783 Saltwater Aquariums, Marine, Aquaculture Applications Magnesium Tester 64 grams

Works great and gives accurate reading.

Easy to use, consistent and accurate against ICP tests

I would give zero stars if I could. This is shameful... Basically useless. The first one I bought would read 1800+ regardless of what I put in the cuvette. RODI water, tank water, or freshly mixed salt water. I asked for a replacement since I thought the first one was defective. NOPE. Still getting 1800+ Mag on tank water, and freshly mixed saltwater. Very poorly performing test kit. DO NOT BUY.

Very good works the way it should

Easy to use and helped get my tank under control. My corals have done much better.

I used this Hanna Magnesium Checker before, but my old unit gave me inaccurate readings — I ended up overdosing magnesium in my reef tank because I thought the levels were low. It wasn’t until my corals started looking stressed that I suspected something was wrong.I’ve now replaced it with a new unit, which seems to be working properly. But now I have to do a major water change to fix the imbalance.I like the convenience of the checker, but this experience taught me to double-check test results and not fully rely on one device.

Seems to match perfectly to my salifert test kit. This Hanna kit is actually a little easier than the salifert in my opinion.

PROs.If you have trouble reading those color charts this is a good option. Easy to use.CONSHanna reagent refill packs are IMHO ridiculously expensive for a few grains of powder.