I only add polyquat in the fall during closing. My spring start up is usaully turn on the filter, shock and vac the pool, then after a few days of filter running test the water and start adjusting pH, Alkalinity, hardness. With your solid cover you may not have to do much, my mesh cover lets in the rain over the winter and I always open to low hardness. I open early to avoid algea problems as the water is cold.