Sea Green Hydro is Sea Green specially formulated for maximum effectiveness in a hydroponic reservoir. Sea Green hydro foams less than traditional Sea Green. It is specially designed to increase nutrient uptake most effectively in a hydroponic environment. Regular Sea Green was designed especially for use in soil.Ê It works just fine in hydroponics, but its not where it was designed to be used. So Sea Green Hydro comes along and is! Like regular Sea Green, you can use Sea Green Hydro in soil, no problem... but it is most effective in the hydroponics or aeroponics environment.