I have switched from the lowest level Tropic Marin to the Bio-Actif about 3 months ago.
I have a 30 gal
reef tank with only a protein skimmer. I asked a fish store owner about the pro reef and was told that that should be used when calcium buffers were used. since I don't have any reactors installed, he told me the Bio-Actif was the best fit for my tank.
He was right and when I switched, all of my corals exploded. I had 6 very healthy Yumas and now I have 16.
Fortunately I have a small PWC
, so the supply will last a while.