So I just plumbed a bare 75 gallon to my sump. I’m brain storming ideas on what to do with it! Tanks 500gallons Current stock are 20”plus ray 22”plus jardini 24” clown knife fish and a small midevil who’s being rehomed soon. I plan on drilling and running the pump externally so it’ll be the whole 75 free water depth is about 13”. Would a Refugium do much in the way of nitrate reduction at that size? Or am I better going the k1 route? I just want to make the most use of the space.