i meant to say that im using 17 3 inch net pots in the 27 gallon tubs, i have a 20 gallon rubbermaid with 14 3 inch netcups. all 3 tubs have an airstone, 2 run 633 gph pumps, one runs the 396 gph pump, all ecoplus, trust me, you want this brand, it has rubber suckers on the bottom of the pumps...