Hello, I just bought a TF-Pro and I am am new to the group. Since getting a pebble surface in November 2020 (one day application, no second day pressure washing and slurry box), my CH has been 600-700. A couple of weeks ago, I began drawing water in order to replace with new water. The nice guy at my local pool store told me draining the pool, even halfway, could damage the new surface (because less weight exerting pressure on the walls of the pool). So, after draining 4 inches of water, I stopped draining and followed his advice — I put water hose in bottom of pool and filled for 9 hours, allowing the pool to overflow. All this only lowered my CH about 150. I would appreciate comments on the best way to replace water: option #1 — pump or siphon water out of pool, then refill with hose, or option # 2 — put hose in bottom of pool, filling bottom of pool with new water and allowing old water to overflow all day. Thanks.