In addition, Premium Series RO/DI units include a valve that provides access to the RO water before it enters the DI housing, useful for accessing drinking water, and it simplifies the process of checking the performance of the RO membrane
Paradoxed":n8dg5bzq said:I bought one of these with a tds meter, with shipping it cost me about $135
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 4319939633