I have a rather large in ground spa (no pool just spa). I am winterizing it as it will not be used this winter. I have emptied it, blown all the water out of the lines. Add pool antifreeze to some of the exposed lines. I filled it back up to below the jets. However the jet lines are rather low. My question is will the remaining spa walls, not under water, crack or become damaged, if left out of the water? This is NOT a plastic/silicone type of spa. Should the water line go all the way up to just under the skimmer? If yes will the jets be ok underwater during the winter? In Apex, NC we do not get extended hard freezes!