On computer: Tell me about it. I bought a new one and had problems with it. I had to go 3 times during the rush hour. >:

I used sera baktopur. It's about 1 drop per liter. You put it in, the recomended dose, wait for one day, and on the 3rd day repeat the procedure. THan do a water change. I did a one more treatment (just to be sure) and did a 100% water change (it's not filtered), and nuked the tank.
Now, everything's gr8:woohoo2