I have a 35gallons tank and what I use is a HOB type ogf overflow.. with a DIY skimmer( I used airwood and an airpump) I have live rocks about 30lbs and a DSB of about 4"...I can see copepods swimming and it's cycling for almost two months now and my clown is still alive and kicking heheheheh is this a good sign? as for the parameters haven't check it yet. still saving money to buy one 