My personal and reliable favourites are the Myron cup 0 - 3000 uhmo, with a switchable push button for much higher conductivity readings when rarely needed. Carry some 2000 uhmo calibration standard fluid with you to ensure proper working status. Used in combination with the button and particular plate etched plate reading on the bottom, you can feel safe about proper reporting of conductivity values throughout the years. Uses a simple 9 volt battery, which you should change at least yearly, no matter how much you are using the device.
For pH I find a simple hand held meter from Fisher Scientific or Grainger works very well. Only costs about $40. and uses a trio of watch type batteries. Always keep the bulb wet with deionized water between uses. Do not let it dry out! A Cotton ball or cut absorptive sponge in the bottom seal cap works well to keep it wet between uses. Also recommend you carry a small bottle each of ph 4.01 and ph 7.00 buffer solutions. A 2 oz. plastic bottle is easily toted for service work.
Using a cut bottom plastic coke bottle is excellent for collecting fountain solution from the reservoir tanks and also serves well as a vessel to hold the solution for measurement taking.
Been to some shops where the solution was so scummy and dirty, I was reluctant to dip my precious tools in the solution. The coke bottom bottle helps separate the slime to the sides to minimize the contamination on the tools. If the bottle gets too dirty just toss it and cut another.
Never use a combination ph and conductivity meter. You are only harboring problems as they tend to go out of calibration easily and frequently. The 2 step method is by far the best route to go.
Hope these suggestions help. D
