This months featured meter is the Hanna Instruments HI 98129 Combo tester. For the nursery person or gardener this is a good value for money tester. It measures pH, conductivity and temperature. To use the tester prepare a solution by mixing the soil with water in a 1 : 5 ratio. Measure hydroponics solutions by dipping the tester into the solution.
The Combo is waterproof so it is good for the rugged outdoors. It comes in two models. Both record pH from 0 to 14 with 0.01 units resolution.
The HI 98129 measures conductivity in the low range so is better for
testing drinking or irrigation water, aquariums or propagating mixes.
The HI 98130 is better for hydroponics, testing nutrient levels in growing
media or envionmental applications where higher salinities are expected.
Both testers have automatic temperature compensation so taking measurements
is easier. 
One of the great features of this tester is that the user can set the
TDS factor. This factor converts conductivity readings to an estimate
of total dissolved solids. For more information on this see our salinity page.
The pH electrode has a cloth junction which means you can extend the life of the tester. When the electrode comes to the end of its useful life don't thow the tester away just replace the electrode.
Another good feature of this tester is that calibration is easy. All
you need to do is have at least 1 calibration solution. pH 7.01 is about
middle range. It is better to have another calibration solution either
pH 4.01 if you expect low pH values or pH 10.01 if you expect high values.
The tester automatically recognises the strengths of the solutions and
adjusts itself.
To calibrate for conductivity just use either the 1413 microS/cm solution for HI 98129 or the 12.88 milliS/cm solution for HI 98130. Again the tester automatically recognises the solution strength and adjusts.
The tester is about 6 ¾ inches long (about 17 cm) so will easily fit into a pocket.
For pricing and specifications see Combo testers in our catalogue.