"Martin" wrote in message
...
I have a real problem with what I consider to be Dirt or sludge in the
tank.

The substance is brown, forms in globules often very very small ones, and
builds up on all my plants. The plants are normally caked in the stuff
(normally at the top and sides where the flow is directed - but is does
form
everywhere). I have resorted to hitting the plants with a net or other
tool
which puts it all back in the water and hopefully the mini Eheim-filter
that
I have in the tank will take it all out. The main Eheim filter is next to
useless as its not removing the dirt at all - this is just acting as a
biological filter.

I've never had such a severe problem myself, but I have a couple of ideas on
what might be going on. First, there might not be enough circulation in the
tank. There should be enough circulation so that this stuff remains in the
water column and gets picked up by the filter. Maybe the outlet from your
Eheim is not positioned in a way that provides circulation throughout the
entire tank. I used to have stuff settle on all surfaces in my tank a long
time ago when I was only using a UGF. Second, are you vacuuming the
substrate with each water change and are you doing water changes at least
every week? If your substrate gets saturated by this material, then any
minor disturbances will stir it up into the water column and cause it to
settle on the plants. It also sounds like you might have black beard algae
on your plants. The algae makes the plant surface less smooth, which makes
this organic material stick more easily to the plants. In my tank, the
leaves that are covered with BBA always have more of this stuff on them then
healthy leaves.
__
Alex
pcalex (at) hotpop.com