I have 2 HOB filters on my 10g tank. One has a rectangular. flat filter with carbon embedded in it, and the other is an older style with a sponge at the bottom and a bag of carbon on top of the sponge. I treated my tank today with Parasite Guard fizz tab and I took out both filters. Now I am worried that the beneficial bacteria are dead. What does a person do with the filters when they remove them to medicate the tank? For stocking information, I currently have One adult female BB Endler (Its sister just died from unknown ? a few days ago), one male BB Endler (both adults are less than a year old), their litter from 3 months ago (approx 6 juveniles), two from the litter a month ago and three fry that were born 3 weeks ago. I also have a ghost shrimp male that is approximately 10 months old and 3 young albino cory cats that have just started to display mating behavior. Tank is planted with a large Argentine Sword, a medium Java fern, a moss ball a little smaller than a tennis ball, and approx 6 sprigs of anacharis. Gravel is small river rock and some special sand for growing plants mixed together. I just put a tbsp of aquarium salt in a few days ago. Water parameters: Ammonia 0, nitrites 0, nitrates very low, ph stable, hard water, no chlorine. Ammonia tested by test tube, all others by test strips. This tank has been running since the spring.