I was feeding twice a day in my old 180g but i had numerous water quality problems and ph crashes i added a kh buffering media to my sump on my new 350 uk gallon system and i feed well once a day and i change 1/3 weekly and havent seen the nitrates above 10ppm..
I have 3 rays very healthy 2 motoro 8" and a 13" orb and about 15 other fish in there cichlids, dat ,tig etc. One thing i do notice is they go mad at feeding as if they havent been fed in weeks..