It has internal built in overflow box. I have about 40lbs of pond matrix as my bio media that is cycling now to establish live bacteria (stability). I will not hookup the protein skimmer until some livestock goes in. I may hook another overflow up for extra filtering, but the total bio load on this tank is going to be pretty small. I do not plan to overstock it nor keep live corals(at the moment anyways). All water will be RO for changes/top off. I don't plan a top off tank either, but all this is subject to change haha. Once it is running further I may tweek things but the goal now is just to get it running.
