Pet Forum / Aquaria / Cichlids / September 2004

You vacuum gravel to remove the detritus before it dissolves (reducing
your buffer, acidifying the water, adding to your biological load
producing ammonia etc).  On a sand substrate, the detritus mostly rolls
over the sand until it settles into an area of low turbulence (back of
the tank, beside rocks ornaments etc).

One sand-substrate strategy would be to arrange your filters so that they
are more consistently vacuuming this detritus, and then clean your
filters more often and do regular water changes.  This is most easily
done by increasing the turbulence and directing the flow so that the
detritus rolls around to where filter intakes are located.  With
Discus/Angelfish, as these fish suffer under turbulent conditions, there
is a limit to how much you can use greater water flow to serve your
purpose.  This makes it a bit more challenging, but not impossible.  Bank
your gravel from the back.  If you have a lot of water-blocks (rocks,
driftwood, plants etc), then position your filter intake at the front of
the tank opposite your filter returns, and direct your flow at your
intake.  If you don't have too much water-blocks, then set up a U shaped
turbulence, so the water flows along the back and across the front back
to the filter (lengthwise to the tank).  The back-flow will break-up the
current somewhat, and then the front-flow should drop down and 'slide'
across the bottom pushing the detritus towards the filter intake.  Adjust
your intake to find the optimal depth where you get the most crap and the
least amount of sand is taken in.

Going to a gravel/UGF setup will not solve your problem as it traps the
detritus, you still need to vacuum, and you are never 100% effective at
removing it.

Another method is to set up an automatic gravel-vacuum, but this is not
applicable to heavily planted tanks, or tanks with foreground plants, so
ymmv.
http://www.2cah.com/netmax/diy_projects/vac/vac.shtml .  Of course, with
a big Pleco, you probably don't have a lot of delicate plants ;~).

Angels tend to be jumpy when disturbed (gravel-vacuuming).  Try to move
slowly, and feed them when you are finished (so they associate a reward
after the intrusion).  Having dither fish and lots of shelter will also
help keep them calmer. hth