The brown is probably dirt that's settled on the leaves or brown algae
which is an indication of low light.

Since it's a somewhat low light tank, 25% weekly water changes should
be enough to replenish other nutrients that the plants need. If you
add fertilizers you're more likely to get other algaes.

Ludwigia and Limnophila have high light requirements and probably
won't last long with just 15w.

Cris

On Wed, 24 Mar 2004 15:14:41 +0000, Commander Vimes
wrote:

Hi all,

I am new to fishkeeping and have a 40 litre tank. I have planted the
tank with a Limnophila, a Hygrophila and a Lugwigia. The tank is
usually lit for 12-14 hours with a 15w flourecent bulb. The plants
appear to be doing well, having been in the tank for 4 weeks or so
now, but the edges of the leave on all the plants are going brown.
This is particularly true of the top leaves.

Being a newbie, I am sure I have been overfeeding the fish and have
cut back the amount I feed them as I get the impression the brown
stuff is waste product as it dries to a brown/yellow dust and is
present on the tops of my filter and heater. It also accumulates
around the edges of the tank.

I have cleaned the gravel today and conducted a 25% water change in
the hope of reducing the waste in the water (tank is fully cycled
btw).

I am not feeding the plants any nutirents.

I would therefore appreciate some advice as to whether peopel think
this is waste/algae or something else such as a nutrient deficiency.

Any advice is greatly appreciated

Vimes