DM-1 Dual Inline TDS Meter Video Transcript

Hey everyone, Aquaman here with FilterDoctor.com. Today we’re looking at the HM Digital DM-1. Now, the DM-1 is a dual line TDS meter. What that means is this unit has two sensors. One that goes in your incoming water and the other that goes in the outbound water after it’s been through whatever filtration process you’re putting it through. In most cases we’re talking about deionizing, or reverse osmosis because those two things remove total dissolved solids; whereas a carbon filter won’t have much effect on TDS. So, this will monitor both the incoming and the outgoing TDS simultaneously. And with a flip of the switch on the front, you can get a reading on either your incoming or your outbound water. And then you simply do a little math to determine how much of a reduction you’re getting, then it depends on your unique system. In most cases, a reverse osmosis system, you’re going to want a minimum reduction of 75%, and hopefully a lot more than that if the membrane is new. Eventually you’ll get as low as 75%, 70%, and then the membrane will need to be replaced. In other cases, with the deionizing resin, you could get very high total dissolved solids reduction for a long time and then it will fall off very rapidly; so having the meter will tell you when the deionizing resin is exhausted. So, it’s a real simple unit, the sensors are replaceable because these tips do corrode over time, that’s just normal from wear and tear. I’m sure you’ll get a number of years out of them before they need to be replaced, but it’s nice to know you don’t have to buy a whole new unit. You can simply replace the sensors if that time comes. It has a thousand hour battery and it has an auto shut-off feature so that battery will last a little bit longer, rather than it being on all the time. It comes pre-calibrated, but it can be re-calibrated using a 342 part per million sodium chloride solution. HM Digital does offer a 342 part per million solution for just that purpose. Unfortunately, the calibrating is not digital, it is done with a mini screwdriver in the back of the unit. Again, this is DM-1, a dual line TDS meter, perfect for typical residential applications. I’m your host Aquaman with FilterDoctor.com. Thanks for watching. 

See detailed specifications and purchase the DM-1 here.