Nastyness on substrate

[Str8linespeed]

I took my rock apart after 1+ year to catch a nuisance fish. There was a lot of crud under the rock and the water was cloudy for a couple days. Since then I have a nasty brown outbreak on my substrate. I've vacuumed the sand while doing water changes to try to get most of it out but it keeps returning. Its been about a month now. Anything I can do to get this to clear up or will it just go away on its own?

 

[mcgyvr]

Thats pretty typical when you go from not stirring up the sand to stirring it up..
Usually if you never stir up the sand you don't have that problem or if you are always doing that you don't have the problem..
Its changing from one practice to the other that tends to cause a temporary bloom..