If any of you are interested, American Science & Surplus (847-982-0870) has the Hanna DiST 3 Total Dissolved Solids Tester on sale for $12.50. It's catalog number 27741 on pg. 22 of their June catalog. A S & S has a website, but the tester isn't listed. http://www.hannainst.com/products/testers/dist.htm