In the complete tank tear down, all the rock went into a Rubbermaid stock tank and had 6PH for flow with a 2 150g HOB filters to get as much stuff out of the rock as possible. The rock was turned and rotated daily. The sand was vacuumed 7 times in a week and I was running fine filter socks and it pulled a lot out. I am feeding just frozen brine and mysis. I feed one, one day and the other the rest. I have a Bubble Magus NAC3.5 and it does wonders. Pulls out sludge. About a milk gallon every 3-5weeks.
A whole cube? that's a lot of food for a tank that size, and the amount of livestock.