Sand?

[roydooms]

What do you mean exactly by white fuzz. Only time I've seen anything like that on the substrate is when it was growing on something in the gravel. You you be more specific/descriptive?

It looks like the white fuzz when fish food gets bad. The thing is I'm cycling the tank with ammonia. No fish food or anything. Its on I'll say 40% of the sand.

 

[Shadowraven]

Could be fungus, but it sounds more like a bacterial growth to me, especially if it is growing quickly. It is not too unusual for these kinds of growths to appear when cycling. Just suck it up with a gravel vacuum and wipe it off of anything else it appears on and suck it out too.

 

[allaboutfish]

i use natural sand that my grandparents get in camden that is filtered and i have no problems you just have to rinse it out so i'd get natural sand you can find!