Good low-range kit
(Posted on 12/14/11)
Comments: This kit is very good down to the 0.10 ppm range, but under that point the colors (similar shades of light yellow/green) are very difficult to interpret.
This test takes about 8 minutes to perform, with 2 solutions, and 17 ml of aquarium water. It is easy to use and the results are consistent (partly due to the volume of water allowing for minor variations in droplet sizes).
The color is light yellow when 0.00 ppm, increasingly more green from 0.02 to 0.36 ppm, dark green at 0.64 ppm, and dark blue at 1 ppm and higher. The colors for 0.0 ppm and for 0.16 ppm and higher are very easy to read, but the steps from 0.02 to 0.08 ppm are very difficult to distinguish. If you need to fine tune phosphate levels in the range below 0.10 ppm, then you need a different test kit.
For what it's worth, you can also perform a High Range test by diluting 2 ml of aquarium water with 15 ml of RO water for results of 0.17, 0.34, 0.68, 1.36, 3.06, and 5.44 ppm. Anything higher than that is dark blue.
I like that the color is based on a side-by-side comparison of one vial of unmixed aquarium water to one vial of mixed aquarium water, so any color or turbidity within the aquarium water is taken into account.
Doesn't seem reliable
(Posted on 1/26/13)
Comments: I've used this test on my reef tank (sps/lps/softie) and I don't think the results are accurate. I followed the instructions to the letter but everything I've tested comes out .08 ish. My tank = .08, di/ro water in my storage bin =.08, water straight out of my RO/DI =.08 (reads 0 tds on my meter also fyi).
I'm reading it under flourescent lights which I believe are "soft white" ~2700k. They recommend 6500k lights. Not sure this is really the problem but who wants to change the lights in the house if it's required for testing???