wierd growth in tank?

Question
I have a 90 gal Freshwater tank. I have large polished stones for gravel. My tank mostly has Dalmation mollies, a couple gold mollies. A catfish and a pleco algea eater. I've had the tank for a few years now, All of a sudden I have a weird growth on the gravel. It's whitish and fluffy and looks like it is growing out of the gravel. It is also covering my artifical plants. It almost looks like Lint or dust. I checked the water and everything is fine with the exception of the pH being a little low. I added a little salt to the water to bring up the  pH. What do you think this is? Is it a type of Fungus? and what should I do to remove it? THanks for your help  

Answer
Dear Sue,
It sure does sound like a type of fungus that tends to grow on rotted leftover fish food and other organic matter. Make sure you aren't overfeeding. I noticed you mentioned have large stones for gravel, uneaten food might be getting trapped in between the spaces of these large rocks and making it out of reach of your catfish and algae eater. I would definately increase your vacummings of the gravel and making sure it is very clean, siphon all the white fungus looking material also. You may have to do some scrubbing with an algae scrubber.

Thorough cleanings and insuring no food is leftover seems to prevent this problem.

I really hope this helps!
Best wishes,
Karen~