well you add just enough Dts to give the water a slight green tint...come back later about 15 minuts or untill the green tint has been filtered out by the clams...
I tend to go with the baby clams , because I enjoy raising them and there a bit cheaper than the larger clams, but then agen I feed mine often, at least three times a week or more....for most people that would be a pita...and the clams end up dieing because they are forgotnen about...kinda like me and a orange cup coral I just always forget to feed the thing...but I never forget to feed my baby maxs lol....