I have a Penguin 350 Dual Biowheel filter on a 29g Oscar growout tank. There is 4 babies, and I mean BABIES in there, yet the water is still a bit foggy. There is great flow, and I have 4 cartriges in the filter, what could be my issue? Thanks in advance to anyone that helps out. I'm open to all suggestions, granted it's a legit one. 

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