There is little to no sand under the rock work as I have my recirc pump returning under the rocks and blowing the sand and debris out. around the entire overflow box. As far as what I will replace it with.. I had no sand on the bottom a few years back and I really liked that from and maintenance perspective. If I do put sand back in, it will be a medium fine sand and just enough to cover the bottom. Less than an inch and probably closer to a half an inch deep.
Good choice Scott, thats what I ended up doing. I aswell just covered the entire bottom with only 1/2" of special grade reef sand. I have never liked deep sand beds and have never experienced any benefits from one either. I like to keep it simple. I also removed my refugium and have received even better results! It seemed that my Chaeto would refuse to grow in my fuge and my deep sand bed in there just collected and trapped debris. The last refugium I had, the deep sand bed turned into concrete and I had to break it apart to throw it out. No more refugiums or deep sand beds for me.
Marc