Regardless of the type of air check or brine pickup tube, there is always brine left in the salt tank. Fresh water (Refill water, softened or hard) classifies on top of it because of the heavier brine staying on the bottom. Refill water will always dissolve any salt it comes in contact with, regardless if the salt is in hollow grid legs or on top of the grid. It takes 2-3 hours to dissolve salt to solution saturation. Plastic grids and their legs are perforated to allow refill water to contact the salt. The people wanting the refill to stop at least 1" above the grid are proving refill water classifies on top of the brine and that just 1" of contact will dissolve salt. Now IF 50 lb block salt is used, there will not be any salt down in the grid legs.