Sooner or later, as with any hobby, you begin acquiring tools that make your favorite pastimes more enjoyable and productive. Scuba divers might buy a sophisticated dive watch, foodies could invest in quality culinary knives and an audiophile might be meticulous in his or her choice of an amplifier. Hydroponic gardening is no different and it definitely helps when your equipment suits your personal needs. For this review will be looking at the Bluelab truncheon nutrient meter with an eye for ease of use, quality and performance.

Bluelab is a New Zealand based company that produces pH meters, conductivity meters, calibration standards and dosage controllers for horticulturists. The truncheon nutrient meter resembles a plastic wand that can be dipped into a nutrient solution for the purpose of measuring the water’s electrical conductivity. For hydroponic gardeners this measurement can provide important information. Pure water conducts electricity rather poorly and given the addition of hydroponic nutrients, water hardness and other factors the electrical conductivity will measurably increase. Measuring this conductivity allows insight into the overall “saltines” of a solution in a reservoir and can be used to better manage your hydroponic nutrient program.

Two varieties of the truncheon nutrient meter are available. First is a standard meter that measures between 0.2 -3.6 EC. There is also commercial model that measures within an expanded range of electrical conductivity; 0.4 - 6.0 EC. While both instruments function in the same manner the commercial truncheon is suited for those working with nutrient solutions that are applied at higher concentrations for a purpose such as salt stressing plants. The standard meter will suffice for a majority of our readers and that will be the focus of this review. Both cost roughly the same. Just be aware that two options exist and because they are so similar in appearance and in name it’s possible to unknowingly purchase one while intending to buy the other.

Truncheon in original box, minus the plastic sleeve.

The nutrient truncheon measures a length of 41 cm (16 in) and has a diameter of 2 cm (0.8 cm) and retails for approximately $130 US. As stated previously, this is the standard model and the primary difference between it and the commercial variant is that this measures within a tighter range of conductivity. Included are two AA batteries, instruction booklet and some additional product literature. Since the plastic body of the truncheon is shrink wrapped and the battery cap sealed with a rubber o-ring, the truncheon is rendered effectively waterproof. Consequently there is little reason to be concerned over accidentally dropping the truncheon into a reservoir and submerging it completely. However, it’s worth knowing that the five-year guarantee does not include damage incurred as the result of water leaking into the truncheon due to a missing or damaged o-ring. It’s a recommended practice to visually inspect the o-ring periodically, just to ensure it remains in working order. For many, this aforementioned five-year guarantee is one of the major selling points of the nutrient truncheon. If that’s high on your list of features, just remember to save your store receipt in a safe place. It wouldn’t hurt to register the truncheon with Bluelab after removing it from the box either. While the printed warranty states the truncheon must be registered with Bluelab within 14 days of purchase to redeem this guarantee, a representative of Bluelab informed me that so long as you possess the original store receipt there shouldn’t be issue with redeeming the warranty. That’s good to know.  

Everything included. Yes, even the batteries are branded Bluelab.

Using the nutrient truncheon couldn’t be easier. It comes both factory calibrated and loaded with batteries so it literally can be taken from the box and immediately be put to work. Since the truncheon turns on and off automatically it just needs to be dipped into a water sample and a reading will be available within moments. This really shines when testing of multiple reservoirs is required. Previously, gardeners using a traditional meter would visit each reservoir with a wired meter which is rather inconvenient to carry about. Alternatively, several water samples would be collected before being carried to a bench top where a conductivity meter would be waiting to test the collected samples. Now it’s possible to visit a reservoir, dip the truncheon with only one hand and record the measurement on a notepad using the second hand. Because of the unconventional appearance the nutrient truncheon might give the impression that it’s difficult or confusing to read. In reality it’s both quick and simple. Just find the LED that’s illuminated read the measured value in units of electrical conductivity, conductivity factor, total dissolved solids of sodium chloride or total dissolved solids of potassium chloride. Don’t feel intimidate by these different terms.  These are just various units similar to how a kilometer and mile are different and the included instruction booklet provides a clear explanation to all these technical terms. Something that wasn’t intuitive to me however was how the index scale on the truncheon appears to be upside down while in use (see picture below).This is a rather minor issue since it’s not difficult to read an inverted number, especially after some repeated use. I can’t help but think it would have been better to have the index appear upright from this perspective.

Please note that Grizzman from the Gardenweb hydroponic forum was quick to point this out; "Also, one note about your comment that the numbers are upside down. This is only true if you're checking a solution at waist height. my reservoirs are placed on the ground. I have to (well not have to, but generally do) bend over to dip the stick into the liquid. Of course, this causes my head to invert which, in turn, makes the numbers appear upright."

No, I don't drink from this bottle.

Several more features that I appreciated; the truncheon’s wand shape allows it to double as a stirring rod for small and medium sized containers while mixing nutrients, the cloth loop on the battery cap allows for hanging on a wall hook and no calibration is necessary for the  truncheon. Furthermore, the general shape and size of the nutrient truncheon make checking multiple reservoirs much easier and ergonomic than lowering a wired probe into a reservoir before pulling it back out. Maintaining the probe is also straight forward. Just remove the probe shroud and wipe down the probe head with some soap that is free of dye and perfume using your fingertip. While the LED indicators don’t allow for the more precise readings provided by traditional conductivity meters, something necessary for work done in a laboratory setting, most gardeners will likely agree that the several convenience factors mentioned previously outweigh this limitation.

In conclusion, Bluelab's nutrient truncheon is a unique conductivity meter that is quick and simple to use. It works straight out of the box, no calibration is required and the five-year guarantee outperforms what’s available from competing manufacturers. If you are looking for a conductivity meter to use in your garden, especially if you are checking multiple reservoirs, Bluelab’s nutrient truncheon will serve you well.

Pros - Simple, fast, fully waterproof, convenient to use and a five-year guarantee.
Cons - Index on truncheon could be easier to read while during use, not practical for laboratory applications.
Other - Don't confuse the commercial and standard nutrient truncheons.

Final Score - 4.5/5 Bilberries