Quick and easy, just fill it half way shake and check the color. It's almost like an immediate drop checker. Great for spot checking!
As long as you know there are only two tests in this, you are set! It’s quick and easy.
This test accurately and quickly provides information on the saturation of CO2 in one's aquarium. My only complaint is that, when I bought, I failed to realize that only two tests come in a pack and that there are no refills. I contacted Dennerle directly, and they said there were no current plans for refills, either. With that in mind, it's hard to recommend these other than for an occasional spot test. Service from Aquarium CO-OP, however, was excellent and I highly recommend them as a source for aquarium supplies.
$4.99 Flat Rate