You really do not need a mechanical filter, your live rock and sand will do the filtration naturally. Will need more information as to what kind of tank you are setting up. Fish only or fish and corals or corals only, then what kind of corals Then we can help you a little more. Just slowed down, it will same you time and money in the long run by not having to buy the right equipment after buying the wrong equipment in a hurry. We all know how excited you are and how all you want to do is get it up and running, but we have all been there and know what you are going thru. One of the most important pieces of equipment you can start with is a RODI unit. Try the filter guys.