I love my closed loop ystem on my 180 no wires in tank at all, I have a peninsula tank 72x24x24 i have a reeflo dart with 4 returns on 2 ft centers 12 inches apart, my rock scape hides all my in tank piping completely. I only regret not putting another closed loop on the return end of tank, I wanted to use mp40's I bought one but i never have been able to tell if it helps, ive tried the settings played with it alot. but my closed loop does a great job and i just wasted money buyiny the mp40, I could have put another closed loop in the end and had the flow i needed. but if you go rimless i would eliminate any powerheads and hide everything the look is uncomparable.