help with algae behind rocks on glass

[dougai]

i need to get it off because i just got a straight blue background and i now can see it...
the algae is brown and doesnt look too appetising to the fish
how do i get this off if my lr is in the way

do i move the rock?
will the fish eat it?
tanks a year old 2 clowns in it 30 lbs of lr
gets no sun
it came on when i dumped in new crushed coral but it comes off in thick sheets
if you cant tell what it is i can have a pic in like 20 min

 

[baggin]

What size tank is it? you dont have to much LR if you restacked it down the middle of the tank and keeped it of all sides of glass you would be able to get to the whole tank with a magnet, or alge cleaning pad

 

[dougai]

its a 40 and i pushed the rock back from corner to corner...
the tank is too narrow so i figured it would give more swimming room but i guess it was my stupidity again...
cant move it now i just got a niger and coral beauty so i dont want to stress anyone out