Needed to measure my KH and pH in order to dial in my C02 for a planted tank; this fit the bill and works great. If you dilute the sample to 10ml you can increase the precision as well.

I am old and crusty and forget how many drops I ve added so I have to start over. Otherwise if your memory is good this test will work for you

We purchased a whole realm of API products from our local pet store. As we got deeper into the saltwater world, we learned about Foster and Smith and Red Sea. We were testing for months with API, finding that our calcium was too low (roughly 280ppm), we added calcium supplements by the truck load, to no avail. We wanted to try Red Sea after doing some research about API and Red Sea, bought the kit from F&S, our calcium was 680ppm. I will never use API anything for more than a cruel joke on someone!! Very disgusted that the company can even stay in business!!

I have three reef tanks in my home, so as you can imagine I do a lot of water testing. I've tried every test kit, and this API calcium test kit is the worst. 1) It uses a slightly inferior chemical test formulation, pre-combining two reagents that ideally should be kept separate until the test is performed. 2) Instead of using the accurate syringe titration method, it makes you count drops which can vary in size depending on bottle tilt and hand pressure. 3) You cannot just swirl the reagent as you add drops. Instead, you have to cap the vial after every drop (a lot of them!) and shake it. This is awkward and ridiculously time consuming. 4) The cap does not fit tight, so every time you shake it, a bit of the toxic reagent leaks out onto your fingers! There's no excuse for this lack of quality. Okay, it is cheaper than the competition, but in this case you get what you pay for, and it is seriously flawed.

Every saltwater aquarist needs to test for KH and calcium. These kits are reliable and easy to use. I've been in the hobby for quite some time and these kits have proven themselves to me time and time again.

Does what it needs to do with good accuracy. Good product for the money.

This is a great kit for those who are looking for an entry level calcium or KH test. They are easy to use and have a well defined end point. The down side is the calcium is measured in 20 ppm increments and the KH is in 1DKH. If you want to know a more precise number to figure exact calcium consumption a higher end kit is better suited for you. The price is great and results are consistent. There is no refill reagents available, a con.

Great value! I have always liked their test kits. They are spot on!