Lets Talk Mulm

[kilyth]

WC is every Saturday morning. I'll see if I can get some pics of it tonight.

[Cermet]

What you describe does not sound like mulm but rather like blue-green 'algae' or really called cyanobacteria; this is easy to remove but forms a semi-ridge sheet. Mulm is VERY loose and easy to move around by the slightest current.

Also, mulm is a sign that your upkeep is very, very poor if it exists in any significant quantity - mulm is just semi-solid fish feces, breaking down plant matter, and worst of all, rotting food. A very bad item to have collecting in any quantity in a tank and rarely spread all over on the substrate unless you just don't vacuum at all and really over feed, which I do not think you are doing.

If the stuff doesn't move by gentile current flow, but sticks to the substrate and even glass, forms sheets then I'd say its blue-green 'algae' and your phosphates and/or nitrates are high. Just saying as a possibility.