I just found 2 tanks in my closet! Woo! Sadly, they are a 2gal hex(tall looking, Ill measure later), and a 1gal corner tank. But, anyway! They've been in use for a loooong time before stuffed into my closet, still usable thou. The last time I had fish in the was about 2years ago, with only male guppies. The reason I stoped using them was because I came home one day and found all my gup's surrounded with this slimey stuff. Did a full water change, figured it was just dirty, put conditioner in and then the fish. Nest day, same thing, only worse. So it went on for about a week, I did the same thing every day. One day I came home and they were all dead, suffocated I guess in the slime, the entire 2 gal hex was like that. I had females in the 1 gal, and they died b/c I forgot water conditioner(opps). Anyway, I had teh under-gravel fileters on both of them, with bubbles. Is they're anyway to clean these tanks so I can use them temporarily for a betta(or 2), I onnly have glass stones in the bottom of the hex(they were in the corner tank, I JUST moved them). I'd like to scower these tanks as much as possible and then try to put something in them, I just dont want a guppy re-peat. So, does anyone have any tips? Instructions? Thanks!