"MartinOsirus" wrote in message
...
I looked this up - and there is conflicting advice re lights - increase
the
light or too much light. Am confused !

Quote from the Krib FAQ:

"Forms in soft brown clumpy patches. In the freshwater aquarium, these are
usually diatoms. Usually indicates a lack of light or an excess of
silicates. Increased light levels will usually make it disappear. Easily
removed by wiping the glass or siphon vacuuming the affected area.

Interesting - doesn't mention excess nutrients or nitrates as a cause - I have
found by lowering nitrates and feeding less - it goes away.