First... I have no clue as to the sea apple.. I researched them just enough to find out that they can nuke a take then gave up very quickly on the idea of having one!
I feed dried nori, frozen Emerald Entre cubes and also my own frozen food blend (a mix of meats and greens)... bits of raw shrimp and silversides for the anemones... I also dose live phyto (home grown) & live brine shrimp (also home grown).. and eventually I hope to culture mysid shrimp...
I avoid flakes and pellets... to me frozen or fresh food beats manufactured flakes any day! Granted that's just my opinion and you may have different results... but so far (knock wood) none of my fish have ever had ich or any other disease and I don't have any algae problems... I read somewhere that some of the manufactured foods can cause algae problems... not sure how true that is.. but maybe someone else with more experience can chime in...