Brown slime on sand

[chicky]

I am not sure if I am posting in the correct forum?
I am having problems with brown slim growing on my sand. I was told that it is possible my phosphate level is to high, but even though I put in phosban it continue's to grow. I have had it since I set my new tank up which is about 1 yr, but I am really getting frustrated with it, it seems that my tank looks dirty all of the time!
Could any please HELP with some helpful advice
Thank you

 

[adam B]

Try increasing the flow over the sand. It likes to grow where there is little flow