Mitch Edelman wrote:
I'm cleaning up a 120 g. aquarium with some severe problems:
the tank belongs to an older man who has health problems and
severely neglected it for what I would guess is close to a year.


Hi Mitch,

I'd got at it slow at first to keep the shock to the fish minimal.
It's quite possible that "old tank syndrom" has set in and the water is
way full of nitrates and disolved solids. Changing the water too
quickly to "fresh and clean" could cause severe shock to the fish who
have grown accustomed to living in this soup.

As for the equipment, that's another matter. Take each piece out and
scrub the dickens out of/ off of it. Clean non'pourus stuff in bleach
and rinse well with fresh water, then some dechlorinator diluted with
water.

The green slimy filmy algae growth sure sounds like (BGA) cyanobacteria
to me. A black out will take care of it in remarkable fashion. I used
this treatment on my 55g and was amazed when I pulled off the covers.
Here's a picture of BGA.

http://www.geocities.com/erviservy/moss3a.JPG

Good luck. What kind of fish?

steve