The fluffy stuff might indicate there isn't enough flow in the tank and the filters are clogged or just a bit too low powered for the tank.
It also means you should get some more flow and check the filters.
Activated carbon/charcoal will be funtional for around 1 week to 10 days then it is not doing it's job. It absorbs tints of the water medications, etc. Not usually needed for simply running your tank, more for specific issues.
Check out my signature link it has a extremely useful article about getting started with all things to run a tank.
One of the most important things is to not change the filter media and not rinse it in chlorinated tap water because you are going to need to cycle the filter / "tank" so that beneficial bacteria aka BB, colonize and grow in the filter padding to break down ammonia and waste. The untreated tap water contains the chlorine which kills bacteria like BBThe article will tell you about the nitrification cycle.
Also you are probably over stocked on fish and likely feeding too much and not changing the water often enough.
What size is the tank?
Baby fish do better with frequent tiny feedings and plenty of water changes. one for to keep the water quality good and 2 to remove possible hormones the adults, and babies can release as they grow up.
There is a bunch to read up on.
You are now doing a "fish in" cycle because it is growing the bacteria with the fish in the tank. This means there will be a need for many extra water changes to keep the water parameters safe for your fish family.