Re-establishing a tank

[kmurray6155]

Here's a tough one...........
I've "inherited" the maintenance and transformation of an existing 55g FO tank. Right now it has about 60 - 70 lbs of live rock, 3 -4" of live sand and is a total mess. All fish died, tons of algae, tons of unknown growth on the rock. My first impulse is to throw out all the rock and sand, sterilize the tank and start from scratch. But it seems a waste of $$$ if the rock and sand can be salvaged. My question is this: Can anything be done to effectively clean and salvage the rock and sand, or is it not worth the effort and possible risk?
THANKS!!!

 

[scopus tang]

I recently did this with 5 different systems at our school - the tanks hadn't been cared for in over a year. We started by removing all the live rock from the systems and placing them in a pile on a tarp on the floor (LR even in a system that hasn't been cared for will still have lots of living organisms - some of your more sensitive species will have died off, but the others will still be there). One at a time, we placed them in a tub of premixed water and scrubed off the dead stuff and hair algae with brushes. We then removed most of the the water and sand and replaced it - did this because the original substrate consisted of layers of different sized sands. Went back replaced substrate with 4 to 6" of fine sand from mixing the sand from all the upper 2" of the original substrate from all the tanks. Finished by putting on about 1" of fresh, new LS. Put all new water in. Tanks experienced massive hair algae and diatom growth for about 1 month, as tanks cycled. Introduced clean-up crew, and now 1 1/2 months later all five tanks have cleared and stabilized and I've begun the process of restocking! LR and LS and definately be saved

, just be prepared to continue dealing with the blooms for a while.

 

[kmurray6155]

Thanks for the advice!! What did you use for your clean-up crew?

 

[scopus tang]

The clean-up crews in each tank consisted of
nassarius snails
cerith snails
turbo snails (asteria, margineta, and mexican)
and
red-legged hermit crabs.
I also added a diamond watchmen goby and lawnmower blemies to two of the larger tanks; and a banded serpant star to one of the smaller ones. I didn't find the blemies or the serpant star to be particularly helpful in terms of the hair algae blooms or debris fallout that occured following restarting the tanks, and would recommend them particularly, but they are cool for the students and I to watch. The gobies do a great job of turning over the sandbeds, as do the nassarius snails.