HORIBA LAQUAtwin Na-11 Sodium Pocket Tester, Range 2 to 9900 ppm for Water, Viscous Liquids, Solids, and Powder Samples

I was concerned about purchasing this after reading some reviews that claimed it was wildly inaccurate. Having a few decades of laboratory chemistry experience under my belt (from my job), I decided I'd make some test solutions and check for myself. I give details of my method and results below, but bottom line is that if you are not getting accurate readings then either you didn't follow the instructions, or you have a defective unit. I highly recommend reading the instructions in the manual carefully (the whole manual, not just the "Quick Manual" laminated card), however in short you need to be sure that you:1) Condition the new sensor before first use (leave 2000ppm solution in it for a few hours -- I left over night)2) Calibrate it (see instructions).3) Make sure the sensor is clean of the previous sample (rinsing it with some of the new sample is a great way to do that, if you have sample to spare).4) Make sure the entire sensor is covered with the sample (egg-shaped area -- see photo I uploaded).5) Close the cover and wait until the measurement has stabilized (a happy face appears on the display).I tested it for solution concentrations between 50 to 4300 ppm. The deviations in all cases were well within the 10% accuracy they quote. I suspect if you're operating near/between calibration points and are careful, you might be able to reliably get a 5% accuracy.As a final "real-world test", I tested a sample of commercial canned soup, and it returned a concentration within 4% of what the nutritional label indicated it should be.I am very happy with this unit. Once you've learned how to use it (not hard to learn, but not "plug-and-play"), it works beautifully, easily, and accurately over a large range. It feels solid and well constructed. They give you a good amount of calibration solution for a number of future re-calibrations and a syringe for sampling. The included storage case is decent with compartments for the unit, calibration samples and syringe, and should serve the purpose fine, but it's made of run-of-the-mill cheap hard plastic -- nothing spectacular there.Overall, I'd recommend the Horbita LAQUAtwin Na-11 if you have the need for such a device.Details for those interested in the nitty-gritty:I used a calibrated high accuracy scale (<30mg error), commercial distilled water (which I assumed to be 1g/ml density), and additive-free commercial salt (Crystal Diamond Kosher Salt) to make four NaCl solutions. The distilled water should have impurity concentrations far below the sensitivity of the device. After a decent amount of research, the best estimate I could come up for the salt was something like 98(2)% NaCl (where the 2 represents +/-2% error). Ideally I'd use lab-grade NaCl, but the 2% uncertainty should be plenty accurate given the claimed accuracy of 10%. So, I assumed 98% NaCl in the salt to convert the NaCl solution concentrations into Na+ (sodium ion) concentrations quoted below. (Note that 1mg/L = 1ppm. So while one actually measures mg and L when making solutions, and the meter reports ppm, they are the same units.)Results:4310mg/L Na+ Solution: Measured 4500ppm (4.4% deviation)1098mg/L Na+ Solution: Measured 1066ppm (-2.9% deviation)570mg/L Na+ Solution: Measured 580ppm (1.8% deviation)53mg/L Na+ Solution: Measured 57.7ppm (8.5% deviation)Note 1: I averaged 3 measurements for each reported measurement. I dumped out the sample and refilled it for each measurement. The individual measurements always agreed with +/-2 in the last significant figure. e.g., for the 53mg/L solution, measurements were 57, 57, and 59 ppm, averaging to 57.7ppm.Note 2: If I had assumed that salt was 100% NaCl, then the largest deviation would have been only 6.5%. Either way, these numbers are very good.Note3: The calibration points are 150ppm and 2000ppm, so the tests include values well above and well below the calibration points.Reconstituted Campbell's Healthy Request Homestyle Chicken Noodle Soup:Label claims 410 mg/cup (1733mg/L) once reconstituted (1 can tap water added).Measured: 1800 ppmRatio: 1.039 (4% higher than label)Tests with potassium (K):Potassium has a very similar chemistry to sodium, so I was curious to how well the unit could differentiate this ion. I used Morton Salt Substitute for these tests, which does contain some additives, so it might not be as accurate, but based on the information on the label, I estimate it should be somewhere around 95% KCl, which should be good enough. I prepared 990 to 11,600 mg/L K+ solutions and found that for all solutions, the meter read 1.0% of the K+ concentration. So, for example, if you have a 1000mg/L K+ solution, it will read 10ppm. I find this acceptable, but you might want to keep this in mind if you have a LOT of potassium in your sample, and are trying to measure a low-concentration of sodium.I may update this post with a better/more reliable results using higher purity KCl, if I feel there might be interest in that (based on feedback), but I suspect strongly that it would reveal very similar results.

Love that the product is small you can carry anywhere. It easy to use. Easy to calibrate. I’m so long out company chose this method of testing. This is a sodium tester.

It's easy to use the enclosed standards to calibrate the device (or prepare your own with deionized water and non-iodized salt).My results for sodium concentration were within 5% of those from a professional lab.

Getting the product to be calibrated with test solutions provided was difficult for the newbie. Really difficult. After frustration, YouTube, and more YouTube, and second read I got the idea. When calibrated it works.I live near saltwalt and my well appears to be more salty in late summer. I have tracked the water for several months. It was at acceptable levels until mid July and then when the summer drought comes the ground water slows and the saltwater mixes in. It more that doubled. It also showed me how effective a Reverse Osmosis system is at removing sodium from that same water. Really useful information.

Like others have said, it worked for a week or so and now will not calibrate. Even when calibrated it was not accurate compared to lab analysis. Waste of money, they will not accept the return.

I learned that the range can be shifted up to about 9000 ppm with loss of precision at the low end. It works well measuring sweaty clothes without any sample prep.

I am very happy with this purchase so far. The instrument is able to record reading for a solid sample.

Used product 2x, already won’t calibrate??