Severa good ways to go based upon the amount of money you want to spend and wheter you want portability rather than monitor andcontrol with a fixed unit. Any way you look at it you are not going to grt real quality buying hobby quality like the American Marine PinPoint, and cheap Milwaukee's and cheap Hanna's. For a quality meter you need to kick up to a laboratory grade metersuch as a Thermo Orion, Oakton or Hach. If you want a pH anlayzer/controller then go to a Great Lakes analyzer used off ebay. You can generally geta $950 to $1350 analyzer/controller for around $50 to $150. These allow you to monitor your nutrient pH 24 hours per day and with a couple small pumps and resrvoirs the controller will manitainyour pH at what ever level you choose. You can also get them to control conductivity at about $100 to $200. Also Oakton makes good pH and Conductivity controllers.

You can get good laboratory pH meters for about $50 to $250 but the price mainlly depends on your patience. I have scads of extra laboratory pH meters. Hach, Thermo Orion, Oakton and Cole Parmer. Once thing you might use to quickly judge the quality of a pH meter is the retail cost of the pH probe sold and typiv cally used with it. If the probe sells retal for less tha$100 then it is a very sda probe. Very sad probes are sold with very sad pH meters. It is very hard to find a good pH probe retail for less than !50 and tha is for one withut a built in temperature probe.

A good pH meter (much better than a Pin Point or Hobby Grade Hanna or Milwaukee) it is an older model so cheap: http://cgi.ebay.com/Oakton-WD-00605-...item4a9b92c7b0

A very good pH meter: http://cgi.ebay.com/Hach-Sension1-pH...item3ca6a24e50