From reading all the info on here about sand i decieded to use partial Silica sand in my tank been 3 months now and my silicates and phosphates are off the wall...Does anyone know if silica sand releases back into the water... I have alot of brown alge growth on the glass..do to hi silicates and phosphates...and yes it is ro water and yes the tanks hase been up for 6-7 months