13k gallon pool, with SWG. I usually drain below the skimmer level in the fall when closing, then refill with either rainwater or municipal water in the spring when opening. This always leaves me with a bit of a CYA deficit (usually aim for CYA of around 60-70). Does anyone use pucks in the early season while water is still cold (i.e. before the SWG takes over) to ADD CYA to their pool? In past years I've just used liquid chlorine for the first couple weeks, then added powder CYA via sock method to get levels up to 70ish.