How do i get rid of brown algae

[lil ape]

I have all of this brown algae on my glass and sand. How do i get rid of it. I usually rub it off with my fingers but it keeps coming back fast(mabye cause i have a 20 gallon). right now i have
1 percula clown
1 green chromis
1 lobster
1 urchin
1 cleaner shrimp
2 emerald crabs
1 sand shifting star
1 cc star
5 snails
Will any of these things eat the algae.

 

[fedukeford]

its diatoms, do you use RO water?? whats your phosphate level?? how old is the tank?