I have a 55g tank with almost 20 different corals in the tank, big and small, cramped up in there.
And I bought a 16oz of DT's 3 months ago and I only used up less than 1/3 of the bottle due to phyto bloom in my tank.
And the bottle is expired now.
I think I am going to stick with DT's
And I have to go with the smaller bottle like 8oz.
The instructions to make 'em are great. good stuff for 500g and up hobbyists thou.