http://cgi.aol.ebay.com/ws/eBayISAPI...tem=2373140299 There is a link to where I got my handheld unit from nice easy e-bay purchase. orp I am not sure but you may browse through ebay and find that there as well. Also a good source for reverse osmosis units. great way of adding a couple of hundred gallons per day to keep all levels low tds and additives... just a thought