Welcome to FishLore nebstew07!! Stop in at the welcome forum and tell us a little about your tank and your interests.
I need you to test your water and give us your readings for ammonia, Nitrite, and Nitrates. Also what size your tank is and what kind of fish you have in there. Sounds like your tank isn't finished cycling and when you throw away your filter media your throwing away what little beneficial bacteria you had. Don't despair, we can help you figure this out.
Meanwhile here are some interesting articles for you to read.
I have a 20 gallon tank. I have 2 balas, 2 catfish, a large pleco, 3 corydoras, 2 rosy barbs and 2 algae eaters. I have 2 hiding places for them. I also have 3 fake plants and 1 live one. I also have a bubble wall and a heater.l I have zero nitrates and zero nitrite. I don't know about my ammonia. So what do I need to do with my filter. I have a two sided filter one is blue and the other is white. It says not to throw away the white one only to change the blue one. I am thinking about getting another corydora, is this a good idea? ??? :-[
I would not get any more fish as you are over stocked now. If you figure very conservatively at 1 inch per gallon of water. The Mass of the fish at adulthood has to be considered also.
amount of fish x adult size = gallons of water
2 Balas x12 inches=24 inches =24 gallons of water
and you are over stocked right there without counting the other fish.
How long has the tank been set up? sounds like it's not cycled yet. Have you had a chance to look at the articles I posted the link for?
As for the filter sponges, most of us don't change the filter sponges just rinse them out in used tank water and put them back. these sponges can last for several years. the copmany who makes them tells you to chaange them because this is how they make money.
Hope this helps.
Welcome to Fishlore! Your tank water should have an "earthy" smell, kind of like dirt. If it smells like sulfur or a stink bomb, you may have high ammonia or some other nasty in your tank. Please get an ammonia test kit and let us know what it says. Since you have no nitrates, your tank might not be cycled. It's great to have you with us!
When you think about it though the rule of 2-3 gallons per inch of fish isn't really that good because you'd need a bigger tank than 24 gallons to house a 12inch fish. We should come up with a better rule of thumb thingy!
J-man that's why I specified that mass counts also. you know like a 1 inch guppy would need less space than say a 1 inch pleco(the poo machine) that's just an example, And no it's not a good rule just kind of a guide line and you have to think when using it.
I would definitely say overstocked and not cycled and would definitely not add any fish.
If the blue thing is like what I use on my Eclipse, it IS a packet of charcoal with a top of fibrous material about 1/4" thick. They vary in area size but the depth is about 3/4" total with the charcoal cell (made of hard plastic with slits in it). Water goes through it before it hits the BioWheel, and the charcoal filter can be removed when it is dirty without upsetting the recycling as the bacteria grows on the BioWheel. The important thing is NOT to wash the BioWheel or replace it EVER. Unless it is washed in cycled tank water (right, Butterfly? ?).
Anyway, welcome to the site, Ben and I'm sure the good folks above can help you. They have saved me and my little fishies on more than one occasion. ;D