Is 15 lbs enough? Finally (finally) getting around to installing this sucker (many thanks to dittohead!).
15 pounds is enough. Technically, you should fill the dome with gravel, the dome is .09 Cu. Ft. on a standard 10" diameter tank. This would be approximately 10-15 pounds of gravel.
How to rebuild a softener http://www.youtube.com/watch?v=8YkJS...ature=youtu.be