I made a couple of Rain Barrels this Spring, 2-40 gallons White Barrels, i'm getting Algae in the Rain Water, color is light Green, is it harmful to container Citrus? Being how my Well Water has around 350 bio carbs i'm using all Rain Water up to Winter then i will switch to Reverse Osmosos Water.

Algae, is not harmful, and will not cause a problem. To avoid algae just paint your barrels black and put a lid over them when you are not expecting rain. To extend your rain water supply,AND to provide calcium to your trees, you can mix 1 part tap/well water with 9 parts rain water. - Millet