I been wanting to add a refugium or sum to my setup for awhile.I am hoping drive down my nitrates a little more.They are up and down due to my over populated tank and feeding of the livestock(especially my sun coral every 2-3 days).My under the tank space is limited and if used there would no were to store my dy goods(wife owns all available closet space left)So that being said I have decided to go with a Hang on the back small CPR AquaFuge(13-1/4"L x 4-1/2"W x 12"H),and remove my hob aquaclear filter.I might put a carbon pad in the output tube when carbon is needed.This will provide a reduction of microbubles also.I am going with a 3-4 inch sand/mud bed.Some new kent marine Biosediment along with some sand from my main tank.I was thinking of adding adding a few onces of Marc Weiss Fundy Old Reef Mud or some other brand, but sure about the mix yet.I am think about taking a small rock from my tank and turning it into rubble to add to the top of the sand bed. I purchased a coralife pc fixture at 18 watts day-light only bulbs to fit on the top. I will probley use some chaeto for the macro.Stuff like caulerpa seems to be illegal here in Cali. Does anyone have any experiance with these types of refugiums or any comments about them?