aquarium gravel rusting?

[root81]

Yesterday, I decided to clean my canister and noticed that the foam was all covered in red/brown debris that looked like rust, which rinsed off easily. After checking my 3.5 gal tank, I noticed a lot of this rustish debris in the gravel.

Both these tanks had the gravel added from the same bag of blue aquarium gravel purchased at walmart.

Anyone seen this happen before?

[rrkss]

Sounds like diatoms to me.

[msjinkzd]

www.plantgeek.net (http://www.plantgeek.net) has some good algae info. Sounds like brown algae, diatoms, which are common in new tank setups.

[J double R]

sounds like the typical debris found when feeding flake food, in the filter, this is normal.. if it occurs in your gravel, you should clean it more.