You could use a good RO/DI unit. If water does not do very well out of unit you cound grape vine more filters onto it.
There are a few local options for Salt and sand. I hope you know to use pure aragonite sand. There is Aqua Tropics, Petco in Kennewick and Richland, Petsmart in Kennewick.
If you want to mail order Fosters and Smith has a pretty good deal on salt if you can hit the shipping specials.
good luck,
Ed
