Hi,I'm new to TFP!! My problem is I keep getting this brown algae year after year in my pool. I have a 15x24 oval 52" deep with a sand filter. I shock,vacuum to waste and the pool looks great! The minute I put the filter on the brown algae appears!! I first thought it was sand coming from under my liner but it's not gritty to the touch. Should I get an Earth filter?Any ideas would be greatly appreciated!