Quote Originally Posted by Ping View Post
Crushed coral will eventually be the cause of nitrate problems . The buffering info is from Aquarium science of the early 1980's.

Sugar fine sand is the best substrate for a refugium.

I have 3 refugiums. One, a 55 with a DSB, LR, and Xenia. The other two are 20L's, one with a DSB, a mix of Cheato and Grape Caulerpa on a 24 hour light cycle, the other has a one inch bed of sugar fine sand with cheato on a day lighting cycle.

All Have some Live Rock, and I put a new small piece of freshly cured rock in each tank about every six months.

If I could afford it, I would have a DSB of Miracle Mud in the 55 gallon. Miracle Mud is great stuff, just very expensive. The good thing is we can get most of the benefits of the mud with a DSB of sugar fine sand that is recharged occasionally with freshly cured live rock.
Peter Im a big fan of your 55g REfugium with xenia, Was very impressed when I saw it in person.