First went in my rock and sand- i used an eheim canister filter that is rated for 60 gallons but i think it is more like 30 gallons. I ended up tearing that tank down b/c the substrate was too corarse for how deep it was and i was getting a LOT of buildup despite reduced feeding and a large claenup crew- but i have since switched it all to a 20- gallon long and im making awesome progress from there