In a couple of days i will be getting 3 more tanks, they are all 36x18x21 inches and hold about 220 litres each, the question is what is the best way to filter these tanks on a budget as im only 14 and my 6 other tanks drain my cash flow quite alot (especially my 175 gal),. also any sugestions for a 48x18x18 tank would be greatly appreciated. btw i have som spare filters i could use they include 1 eheim 2213, 1 eheim 2211 1 interpet pf3, 1 interpet pfmini a couple of powerheads and about 5 air pumps. 