The G Man wrote:

My new aquarium has been up and running now for approx. 3 weeks and the
fish seem quite happy. All eating and swimming as normal.

What I have noticed is that the features I've added to the tank have a
brown colour covering the surface off them. I assume this is algae as
in the posting by Elaine earlier.

Have completed a 40-50% water change last night and the water looks a
bit clearer.

Is this algae harmful to the fish and is there any way to get rid of it
without removing everything from the tank to clean it?

If it's not harmful, will it go away naturally?

Can take some readings from the tank tonight if you need any extra
info.

G Man,

The brown stuff is called Diatoms, and they flourish with high levels of
either/and Nitrates,
Phosphates and silicates. Low level, low spectrum light can also encourage this
growth.
They are by no means harmful, just an eyesore to some. What I do with mine (I
get them
build up over a week) is to scrub the sides of the tank and the bottom before
doing a water
change, let the filter catch some and then rinse the filter media in the tank
water.
Seems to do the trick and isn't too much hassle.