It is an API liquid test, came with the master kit that also has separate nitrite, nitrate and pH test bottles.
I have everything from jungle vals, rotala rotundifolia, Amazon swords, crypts..all in the 55, and oval ludwigia, spiral crypts and wisteria in the 29 which are going crazy. Gah. Should I just go buy a crapload of anacharis (very few plants available locally) and stuff it in? :/