Hanna Marine Alkalinity Checker HI755

Bought this so I can calibrate my auto tester. Super easy to use. Clear instructions. Repeatable results. Bought all 3 testers for the parameters I test for regularly.

Accurate results and easier than the API test kit

I purchased this to save time on doing tests. You have to do the same abount of test to get the same results. I thought all i had to do was put the water sample in and i would get a reading. Nope you have to mix with another reagent etc etc

First Alkalinity test was at 177 when I tried this item. Now I can keep an eye on it with this tester.

An outstanding device. It was shipped quickly.

So I am not reviewing this last one I bought but one before. I had been using it for years not knowing it was off by over 3dkh! I wondered why I no longer needed to dose but thought since Iost some coral was why! I also wondered why my saltwater mixed so high! I was about to lower my dkh so I ordered this new one not realizing it wasnt ppm. So I returned it and got ppm. The new one was reading over 3 ppm lower, this one too as I checked and converted over to ppm! I also verified with my lfs and my hanna checker calibration vials. The old one wasnt in the range the new one was but at the low end of the range! There shouldnt even be a range. The calibration fluid is always the same so the dkh should be the same every time you test it so that tell you how unrelieable their products are! Its definitely worth the money to invest the the calibration vials especially if you are getting readings that dont make sense!

I have other Hanna digital instruments to take care of my pool. This is totally unreliable. Got different samples of pool water using the 2 provided bottles. One with clean salt water for reset the C1 value and another one with 1ml of solution as requested dor the test for the C2 results. Every test gave me different results ( from 0 to 51). Pool pump worked all day long with fountain as well to be sure water was not still water.After 3 tests during the day and different results I returned this product because or it's broken or it's ineffective. I measured later with a professional (L1 level) digital instrument the real value was 151ppm.

Good device, more expensive than other measuring methods but easier. At times it is off, sometimes I've had to do it twice