So what i did is used 4-4gallon storage bins and a 27gal at the bottom top 2 are mechanical, im using filter floss and filter pads, the bottom 2 bins i have filled with bio balls and put 2 ammonia preventive pads on top of the bio balls. I have a 75 gallon aquarium im using for an extra water volume I attached a dual overflow box to the 75 gallon and running that to the DIY filter which has a 900gph pump that is going into my 500 gal. Then i attached a tube onto one of the return nozzles that is in my 500 gallon which then runs back into the 75 gal. aquarium. I was thinking about making the 75 into a planted tank, what do you guys think or is there better options i can do with the 75