I was cleaning out some clogging on my Aquaclear 110 intake tubes and noticed it smelled like mildew. There are a few bio rings that have mildew spots on them. My air driven sponge filter came from a lfs to jump start my cycle when first setting up the aquarium. It is a 125 gallon with fish added 2 weeks ago after fishless cycle. The fish all seem to be doing well. I haven't cleaned the sponge filter yet, but the air hose became unattached. When I lifted it, I smelled a mildew smell. Do I need to replace the sponge filter? Will that get rid of too much bacteria for the cycle? I want to change out that filter for a course sponge anyway, but I'm concerned it will just seed the mildew/mold to that sponge if I leave the old in with the new for bacteria transfer. I haven't noticed black on the Aquaclear media other than the few bio rings that I removed.
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