i am admittedly a rookie here, but if it were my investment i would completely disconnect the system (or have someone more qualified do it more likely) let it cycle for a day or two, then test again and make adjustments according to the BBB methodology. since copper is the active ingredient in algaecides it's unlikely that you will have severe problems immediately, but just to be safe i would try and let it cycle a couple days with the system disconnected before i added anything else to the water.