ro water= no more diatoms on the sand ?

[DEAD_BY_DAWN]

i dont have enough cash for a ro unit so i was considering buying it from safeway,more expensive in the end but better than tap water (thanks blue_tang) ok so will the use of ro water get rid of the diatoms that form on the my sand,everything else is close to perfect corals are all doing well i just cant get rid of the brown diatoms on the sand it makes the tanks look crappy and dark,i was also going to add another powerhead to will this do the trick ?.