A good deal of that spray evaporates before it hits the tile. Scale formation on tile is reduced when the spray is turned off. Plug the overflow line when the pool is in use. Again, keep the pool water in the pool. Reevaluate the frequency of backwashing if your pool has no separation tank.
Most people backwash more frequently than necessary.
This wastes water. With reduced filtration time, it is particularly important to maintain an adequate chlorine residual at all times. To do this on pools with erosion type chemical feeders, it may be necessary to supplement chlorine feeding by hand. Maintain pool pH between 7.2 and 7.6. Your pool should be initially treated with conditioner to achieve a minimum of 30 parts per million.