Their tank is a 400l system. 250l main tank and a 150l sump. I feed them 6-8 times a day. An auto feeder feeds them 5 times with tetra discus food and new era discus pellets. Then I feed them frozen bloodworms, freshly hatched brine shrimp as well as the profs frozen benkers discus food. I also use new life spectrum foods as well. Excess food is siphoned every day, with a water change being done twice a week. Usually 30%. I am getting an RO unit soon. And then most of my new water will be done with RO water. I have a 1000L flow in as a water treatment reservoir.