Aqua Clear Sponge Filter Turns Red

Are you feeding something different lately? Some flakes will do that.
 
Are you feeding something different lately? Some flakes will do that.

I feed them the same fish food as always. My fishes colors all seem to be dark and beautiful so I'm assuming they are happy. I've been monitoring my light times and water changes so I guess I will just wait for now. Thanks.
 
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