The 9 Best Turbidity Meters

For anyone who needs numbers they can trust in the field, the Apera TN400 is the safe choice. Its infrared light is thrown off less by tea-colored water, and it switches ranges on its own. The kit arrives ready to work, with a hard case, sample vials and polymer calibration standards that are safer to handle than the classic formazin. A color screen walks you through each step. The standards expire after about a year, and replacements add up.

On sale for well over a decade, the Sper Scientific 860040 keeps turbidity checks plain and quick. Calibration uses just two standards, clear water and a 100 NTU solution, and wraps up in about a minute. A lid closes over the sample well to block room light, and a hold button freezes the reading. It runs on AAA cells or an optional wall adapter. With only two calibration points, very muddy samples get less of a check.

Water plants that report to U.S. regulators usually work to the EPA's Method 180.1, which calls for a white lamp, and the Apera TN420 is built around one. A full set of polymer standards comes in the kit. It charges like a phone, runs for up to about 20 hours, and Apera rates it to survive a dunk. A sibling, the TN500, adds a log you can copy to a computer. Tinted samples read low under white light.

Home brewers, aquarium keepers and well owners who want a quick clarity check can start with the NEWTRY SGZ-200BS. Besides NTU, it shows the haze units brewers use, and the backlit screen stays readable in a dim garage. A wall adapter comes in the box, or it can run on batteries you supply. The low ceiling is the catch: it stops at 200 NTU, so muddy creek water has to be diluted with clean water first.

If you sample all day and want the numbers on a computer later, the Amtast AMT27 fits. It stores 100 readings, sends them over USB, and can draw power from the cable when its batteries run out. An infrared light handles tinted samples well, and the range runs past 1,000 NTU, so storm runoff fits. A continuous mode tracks a sample as it settles. Amtast posts little beyond its own spec chart, so plan on leaning on the manual.

The GIDIGI GX-T1 packs four calibration standards, sample bottles, gloves and a dropper into one carry case for a modest price. That makes it a sensible kit for a science class or a watershed volunteer group that wants to start sampling right away. It reads up to 1,000 NTU with an infrared light, and calibration is a push-button routine. It's a newcomer with only months of sales behind it, so nobody has shown how it holds up.

Shops that already trust Extech handheld meters for other jobs will find the Extech TB400 familiar. It has been sold for more than a decade, and the hard case holds the meter, calibration standards, vials and batteries. A zero key resets the baseline before you start, and hold, minimum and maximum buttons make spot checks quick. It reads from nearly clear water up to 1,000 NTU. It keeps no log of past readings, and owner feedback is sparse.

Labs that keep compliance records get the most from the Hanna HI 98703. Hanna built it to the U.S. drinking-water method and the matching standard lab procedure, and a reporting mode rounds results the way regulators expect. It calibrates on up to four points with the supplied standards, stores 200 readings and sends them to a PC. Tags placed at sampling sites can stamp each reading with its place and time. It's a big expense for hobby use.

The LaMotte 2020t comes from a company that has made water-testing kits for schools, labs and watershed groups for generations. It uses a white tungsten lamp, has a USB port for moving results, and arrives as a full kit in a case. LaMotte pitches it for natural waters and mid-range industrial samples. Documents are hard to find outside LaMotte's own site, the seller's description muddles the light source, and few owners have posted feedback.