Oh, just so you know, the cheapest way to get Soda Ash is to go to your grocery store and buy Arm and Hammer WASHING Soda, in the yellow box (not baking soda). Washing Soda is IDENTICAL to the pool store pH raisers but costs far less--around $.80/lb here in NJ. pH Raisers like pH Up! are nothing but Sodium Carbonate...Washing Soda.

That may well change your cost basis for the soda ash method.