<a href=showthread.php?s=&postid=13300728#post13300728 target=_blank>Originally posted</a> by shuguley
Give the sponge filter time, it will eventually be enough to control ammonia for 1 or 2 small fish. My QT is bare bottom, no LR no LS... just pvc pipes, a heater, and a sponge filter. The thing with a sponge is, it takes time for the beneficial bacteria to build up on it, just like when you cycle your LR in your DT. For this reason many people keep the sponge in their sump when not in use in the QT.
The first time I quarantined with my setup, My sponge had no beneficial bacteria on it. I was doing water changes every other day, and using Amquel+ in between water changes. This went on for 4 weeks with 2 clownfish. Now I have a wrasse in QT for 3 weeks, the sponge filter is working now, so I have not had any ammonia spike at all and have just been doing weekly 10% water changes.