Hello All, We have a concrete tank which has been cured and a first harvest was done. The fish (just Tilapia and Nutter) did not put on any weight and growth. That was because the aeration was very poor and the water quality was very bad. This was designed by another person who had not much clue what he was doing. Here are some facts Tank volume: 15,500liters filled volume: 12,800liters Number of fish to add is 700 all would be harvested at 300gm 4 Growbeds from 2 IBC tanks Latter after the harvest i added 3,000 liter swirl filter 1000 liter sump tank, 250liter mineralization tank 250liter Biofilter with 20L K1 Media. Could somebody please advise me the calculation to size the Biofilter and the Growbeds. Currently i have about 715 fingerlings of avg weight 8gm feeding 1mm pellet feed.