Think you have phosphates in your tap or aquarium water? This test will tell you. As usual with any test kit made by API, this test is fast and highly accurate. API makes great kits and this one is no exception. Works flawlessly.

I used to use a more expensive phosphate testing kit from a science education catalog. I found this and decided I could try it out for over a 1/4 of the cost. I had to adapt it to meet the needs of a Middle School Science classroom, but it worked great. I found the tests to be pretty accurate, but it wasn't the most reliable method to test for phosphates around our school. I will continue to use them however, because of the ease of use and the cost.

I have a few planted aquariums around my house, 2 low tech, and 1 high tech all decked out with everything you could imagine. I mix my own fertilizers for the high tech tank and dose for a specific amount on a daily basis. I ordered another companies phosphate test kit, while it was very accurate it was a little cumbersome to use compared to API's version. The API version of the kit comes with a glass tube much like their other kits which I prefer over the tray method I used in the other brand kit. The API kit appears to be just as accurate as the other brand in my comparisons and makes testing for phosphates a little less time consuming. The color chart that is included is a little difficult to read, the lower levels are very similar in color, but I have come to notice the subtle differences over time.

Easy, perhaps the only thing i've noticed is that is not as accurate as I would like. If making two tests simmultaneously, sometimes the results very a little. A little in a test for my aquarium is the difference between having algae nightmares or not. I think this test is only a reference. As other aquarist say, if you have algae, you DO have phosphates. Don't trust the test and use something to low down them.

Seems to work fine. When levels are up a bit, I use PhosBan. Julian Sprung's formula. That also works well.