R/O water is stripped of everything it has no ph no hardness no salts no minerals nothing. To use it in our aquariums we must add all the good things that water needs. Seachem Neutral Regulator adjust PH to neutral PH ( 7.0 ) from either a low or high ph and maintains it there.It also removes chlorine chloramine or ammonia. Kent R/O Right is a specifically formulated mixture of dissolved solids (also called general hardness or GH) that returns the natural water chemistry to reverse osmosis, distilled or de-ionized water for fresh water fish and plants. Provides a balanced electrolyte system which includes major salts, magnesium, calcium and potassium together with all necessary minor and trace minerals. Contains no phosphates or nitrates. If you are doing a planted aquarium, use Seachem's equilibrium. Ok I'm doing this post on a I pad and my finger is tired go to Drsfostersmith.com to do more research.