Just purchased home with a pool and attached hot tub. We would like to close the pool but leave open the hot tub so it can be used (we never used all summer as too hot). Everything runs off same system and a pool company said it should have a built in freeze guard so I could cover the pool for winter and leave the system running to use the hot tub. It is a salt system so they also recommended adding chlorine since salt would stop working around 58 and turn the water green. Does this all sound ok to do? Also if ok to do would you recommend adding a cover to the hot tub so heats up quicker/retains heat? Thanks