substrate dust.

Don't be scared. LOL! In the long run, people report good results. It just seems like it might be a little bit of a pain until the roots take hold. Look into one of those "tom's aquatic gardener" tools. Probably one of the best $10 I've spent on the hobby. It allows me to be much more casual about maintaining the plants in the tank.

About the batting. I have an aquaclear 50 that for a long time i only used two sponge filters in with good results. I just sandwiched the batting in between the two sponges and it clears the tank much, much faster of any sediment that gets churned up. Clean out the filter often until the water clears and you should be good to go.
 
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