Just FYI for any curious, those fish above even though both tanks are BB with sump and auto changes the fish until 4" were grown in a 40b with only a heater and sponge filter with 95% daily, sometimes 2x 75% daily water changes via semi automated system. At 4" the amount of food they ate and waste dropped off - so moved them into the above tanks. With the ro/do awc and pothos nitrate via salifert test doesn't rise above 5ppm. Of course there is plenty of purigen, uv and a oxidator too.
