clearish oily haze coming from gravel

Question
Hi Karen, I recently asked you a couple questions about using creek rocks for my 90 gallon african cichlid tank im setting up and followed your instructions.  Yesterday I put 3 small africans in and while searching the tank for them I noticed I have a fuzzy white almost mold looking growth on one of the rocks by a little crusty thing I apparantly missed when cleaning and I have a clear oily haze thats kind of attached to the gravel in a spot as big around as a half dollar.  Please any suggestions would be great!!!  Thanks.

Answer
A big hello again Jay!
What bad luck! The fuzzy white could certainly have been from something deep in a rock crevice that you could have missed. OR it could be from uneaten food. Manytimes uneaten food can rot and grow fungus in your aquarium. This is just a thought. Whatever that odd stuff is I would do a very good gravel vacummn and remove at least 30% of the water.
I know this doesnt sound good but maybe it would be best to take the rocks out and scrub them well again. If you missed some dirt or other debri in the rock crevices, this could certainly cause such a problem. You could try taking the rocks out (if it isn't too terribly many or heavy to lift) and scrub them in a aquarium safe bucket of strong salty water. This should do the trick for sure. And a good water change with gravel vacummings should get rid of the odd haze in the gravel and the fuzzy white material. I've added MANY rocks everything from Pink granite, unknown round stones to marble rock that have been outdoors for years into my aquariums and I have never had a problem like you decribed. Maybe it was simply something you might have missed.

I really hope this helps and I wish you only the very best with your African cichlid aquarium!
Karen~