Not slimy, light green when dry, chalky.
Is it the color of the Statue of Liberty?
Have you used any pool chemicals containing copper - algecide, chlorine booster, etc?
Does the Intex Krystal Clear have a copper ionizer unit?

I think Watermom may be onto something regarding metals. I'm thinking that maybe dead algae or some other precipitate is stained with copper giving you a light green cloud. I recall PoolDoc has also metioned Iron staining green in some circumstances.