Get Clearex or Final Phase this will help disolve the salts in your medium. I'm pretty sure h2o2 will kill any beneficials that are in your medium. (you don't want that) Make sure you use 3x the amount of water your container holds. So you would pour 3gal in a 1gal pot. If your using ebb & flow, pour the water on the medium rather than flooding the table. Flooding the medium will leave salts on the top.