Wow, 75% weekly?
I've been running my 5g soft-coral nano without filter media or skimmer and it seems to be doing fairly well with 30% weekly changes and a light bioload thus far, although I think I'm going to get rid of the GSP in there, as they're dead-set on taking over the tank.
That being said, are you doing a 15-20% change daily Anthony? I always thought that changing that much water so frequently shocks the corals to some extent, is that not correct?
-Dylan