Thanks everybody!
The pvc is just a holder for the pc lighting I have over the refugium.
I use a bare bottom because I'm going to try my hand at sps and I'll use lots of flow. Maybe too much for fine sand and that's all that I would have used. Instead I used a semi deep sand bed 5" in the refugium with a rack holding LR above 1" and some cheato in a space between the rock.
that is a pretty cool way to hold the lights above the tank with the pvc and also a great way to life the rocks of the bottom of the tank.
