I recharge for about 6 months. My experience is Rowaphos brand,can only get recharge maybe twice and then substrate change to a copper color and loose the strength. Rowaphos when new last me 3 weeks, recharge only 1. I try BRS high capacity. First week of use got a brown film over the sand and rocks really bad. Gave it a chance, change filters on RO/DI unit, bulbs try everything possible; recharge 1 time held the capacity but let go because when using Rowaphos never gets the brown film on sand. I always kept it wet but I read it can be bake to dry.