I have a 5+ yr old 75G reef tank. Despite always using RO water, I have a major hair algae problem. :cry: Approx. 80 lbs of live rock (all covered in mats of algae), and approx 180 lbs of live sand (crushed coral??) over an eggcrate plenum.

I suspect the plenum is the culprit (nitrates leaking ionto system??) – so I plan on taking the tank down, removing the eggcrate/screen plenum, thoroughly cleaning the tank, and setting it up again. I have several questions:

1. Do I even need a DSB? Could I simply have live rock on the bare glass bottom?

2. If I do need a DSB – could I re-use the existing bed? I would plan on removing the sand, stirring it up to remove as much detritus as possible, and then replace it directly on the glass bottom. Or, would I be better off using new substrate? Does the 5 yr old sand lose its buffering capacity?
3. If a new DSB is needed – what’s the current thinking? Sand? Crushed coral? Aragonite? Don’t even mention Southdown - I live in Atlanta, and have never found it.

4. Is it likely that after a thorough scrubbing, I could re-use the live rock? I’m thinking of scrubbing the heck out of the rock under hot water in a bathtub. I realize the freshwater + chlorine will not be good for any critters on the rock, but I’m hoping this will get ris of as much hair algae, while not killing off the bacteria within the rock.

Any other ideas?

Thanks in advance for comments/suggestions.

ss

Well, if I were you, I'd attack the algae WITHOUT removing the rock and scrubbing with tap water, etc. This will kill off much of the life that you have on the rock. I have no idea what effect the plennum has on the nitrate levels, such debates have been waged many times.

Personally, I have a DSB of 4-5 inches in mine. I used regular "play sand," not the southdown variety. I've had no trouble with regulating pH levels or maintaining alkalinity, so I'd have to say that the buffering effects of aragonite are over-rated.

When I had a hair algae problem, I battled it in a couple of ways. 1) manual removal, pull all of it you can from every nook and cranny possible. Take the rock work apart to do this, but don't remove it and scrub it. 2) get plenty of algae control critters. Increase your janitor crew, a dozen or more scarlet legged hermits and a couple of dozen various snails, and best purchase of all, get a lawn-mower blennie. He'll go to town on hair algae. 3) increase your water change schedule to reduce phosphates and nitrates.

As far as the sand bed vs. glass question, there are several supporting glass bottoms now. Personally, I like the look of sand on the bottom and haven't seen any problems with a DSB since 1999. So I'm a DSB guy.

HTH,

Stevesfl,

I don't know if you ever check out www.wetwebmedia.com, but here are some articles you may want to read.

http://www.wetwebmedia.com/deepsandbeds.htm

http://www.wetwebmedia.com/marsubstr.htm

The second has a particularly interesting segment on organisms' preference of substrate. :o

Alicia