Plumbing for my MR3


New member
I have an Iwaki MD70RLT pump feeding my new MR3 skimmer. I am trying to plumb it in. My stand has my sump and refuge in it so space is tight. I am going to stand the skimmer next to my tank. Now the hard part. My sump has 2 3/4" bulkheads near the bottom of the water column coming out of it that are not in use. I was thinking of linking them together in this sort of configuration to save space:

-T l
l Pump

The 7's are 90s and the T is a T. This would work but my only concern is that the three nineties on this pipe would restrict the flow to the input of the pump. I am planning to enlarge the 3/4 bulkheads with a slip adapter to make all this new piping 1" to match the pump input.

My other option and the simpler one would be to do an up and over which would come from the bottom of my sump, up over the top of the sump wall, and back down to the pump input. I would like to do this for simplicities sake (and to avoid draining my sump) now my only question is how do I make sure that this loop always stayed primed so if the power goes out to the pump it won't run dry on the restart. Please I need help on this so I can hook this thing up tomorrow.