mold or fungus on new gravel covering old gravel

[deedee71]

Hi

I have purchased new gravel to go in my fluval chi, I thought I'd save the existing gravel and put it in tights and keep it under the new gravel, but the new gravel above the old gravel has got a film of grey fungus on it.

I have siphoned most of it off. Should I take out the old gravel and give the new gravel a good wash in tap water before putting it back in? I think it must have something to do with covering the old gravel, suffocating the good bacteria and I want to get some shrimp but I can't with this fungus, I've never had it before .

[Mustafa]

If you wait long enough that greyish film should disappear by itself. If you can't wait, then you can go ahead and wash the gravel. Obviously, there was something organic in that gravel to cause the fungal/bacterial growth.