saltyreefguy
Member
i am putting a 135 together, previous owned, there are 4 holes drilled in the backside, with center overflow. so the 4 holes are drilled in a rectangular pattern, i have never down a closed loop system, so i was wondering can i use the 2 holes out of the 4 to make a closed loop, and some help from scratch on how to put it together would help. thanks.