What kind of algae is this?

[brandonboy119]

What type of algae is this, what causes it and how do I get rid of it.

Set is 55 gal
sand w/ peet moss and clay substrate
cascade 1000 filter
green machine uv
23 watt cfl 6700k x4 ( 9hr per day)
ferts are PPS daily 5.5 ml each
water change about every 10 days of 20- 40%

Fish are
Bolivian ram
GBR
EBR
Cockatoo x2
checker board cichlid x2
oto x3
clown pleco
congo tetra x6
and wedge rasabora x10