I had Red Sea Magnesium Test which always measures 1600 ppm e.g. off the scale. Reverted to a Salifert Test which showed Magnesuim about 1300 ppm e.g. a bit lower than I wanted. I had my Salt analysed amd later the reagents replaced - same result. With titration tests, it doesn't always seem obvious to me if the endpoint is reached, so...
Over Xmas, in a weaker moment, I ordered the Hanna Alkaline(dKH), Calcium and Magnesium Tests and also the Nitrate HT and Phosphate ULR. The Magnesium measures 1430ppm with the Hanna Test (new liquid and Powder version).
I will be testing some freshly made Salt Mix to confirm that the Hanna is about 1350 with a Stock Solution.
My take is that I'm not very good at noticing the end points of Titration Tests e.g. the Red Sea Test reagents were replaced and I still can't get it to work. So, for me, the Hanna Tests are very repeatable. I'm aiming for a stable setup so being able to repeat stuff every week and see trends is what's important to me.
The Hanna tests are easy to use and I don't doubt that they are accurate. They do have a margin for error which is perhaps a bit conservative, so results fall well within their tolerances (by design). The company also makes other tests for Commercial rather than Hobby use r.g. comparatively expensive vs cheap (relatively), even so, they seem to all do a good job.
I did invest in some additional items: two water squeezy bottles - one for deionised water and the second for the sample under test, and some deionised water. The most critical test being the Calcium one, which uses only a small quantity of salt water so might be affected by the quality of the water that is used in the test. My own RO/DI tests higher than a commercial deionised water (15 TDS vs 0 TDS). Results of Calcium (like all the tests) are what I expect but easy to get right - I guess I'm not a titrate person.
One small criticism of the Hanna Tests, is how the water sample is added. Some include a pipette and others don't have one. I don't necearrily want to use the 1ml syringe 10x to add sample water. The extra water bottle avoids the need to use their pipette (or to share it across kits). A second criticism, is the black boxes aren't labelled - that's OK if you retain the sleeves, but it would have been nice if they labelled the boxes. One of the inserts was a bit loose but by swapping it with one of the other kits, everything plays nicely.
A second critism is the use of the Timer on a long press. They could easily have made this the only option. I haven't messed up a test (so far) but with some being straight away and others with a delay e.g. 3 minutes, then not having to remember the long press would have been better, IMHO.
Simon
