HM Digital DM-1 In-Line Dual TDS Monitor, 0-9990 ppm Range, +/- 2% Readout Accuracy

This is a compact in-line TDS meter with two sensors. This enables a reading to be taken from two positions in an RO system. In my case I prefer to take a reading immediately post-RO membrane and a second reading post DI, the final permeate. The reading from either sensor is selected by a button for each sensor. I have checked the accuracy using measurements taken by a professional grade WTW conductivity meter and I can say that this HM device is accurate enough. Installation is straightforward. The two requisite T pieces are provided. Note that the sensors are not designed to be read water in a receptacle and will not display an accurate reading. The device is intended to be used in-line within the tubing of a live RO system. Also note that inserting the sensors into the upright of the T piece does require some force, they will not simply push in easily like a length of RO tubing. The resistance must be overcome for a correct installation. It is best practice to install the sensors into each T piece before installing the T piece. This allows you to squint through the open end of the fitting and ensure that the two sensor prongs are clearly visible and facing you as a pair and are both visible poking down into the fitting, like a pair of posts. Otherwise the device will not read accurately.

So easy to install, accurate and well made

I bought this to replace a similar device which had failed. This one outperforms the other in every way. I already have one of these which has been in use for several years alongside to one which failed and I have only just had to replace the batteries although, to be fair, it doesn't get a great deal of use. The batteries are LR44/G13/SR44W which I bought some time ago for something else but cost less than £5 for 100 from Ebay. There are no clibration adjustments so it is possibly not as accurate as some but more than adequate for most uses and with only simple on/off and in/out controls it just sits there and does the job.

Once installed which is so easy a 2 year old could do it, you just have to press the button to turn it on and look at the screen, no messing about like the hand held TDs metre. Great peace of kit at a great price.

Good device operating just as expected. Very pleased.

Very simple to setup and use, would definitely reccommend. Tip: The probes fit tightly into the T piecee - give them a good, hard push into place so yiou can see them through the top of the T.

Allows me to know what our readings coming into our RODI system and also what's coming out. Would recommend

Seems to be working fine atm I need this for my ro unit and the importance of 0 TDS is paramount to keeping a marine tank. It would be benificial to have instructions where to place the TDS unit within an ro unit fixings as it took me along time through various websites to get it right.

洗車用純水器のお手軽数値測定のため導入。すでに純水器2台連結で運用してるのでそれぞれの出口に設置。 そのままでは装着できないのでホームセンターで砲金オネジチーズ、takagiのG1/2メスコネクター、ネジ付き蛇口ニップルを２個ずつ購入。amazonの一緒に購入されてる商品からクイックコネクターも準備。 別途準備したものの方が金額倍くらいかかりました(汗 苦労したかいもあり無事装着でき測定できてます。他レビューから防水ではないみたいなのでモニターの設置場所は検討中です。

Fácil instalar, confiable, me ayuda a ver como esta mi sistema

Works well

المنتج سئ ويعطي قراءه غير صحيحه جربته ووضعت مياه في كوب وسجلت قراءه المدخل والمخرج وجدت القراءه مختلفه في نفس الكوب بفرق من 5 ٪ الي10٪ درجه كما انه غالي جدا وهناك منتجات اقل سعر واعلي كفاءه وجوده

Fonctionne très bien, me semble à présent indispensable pour lon osmoseur, je contrôle la qualité å la sortie de l'osmoseur et å la sortie de la rėsine. Ça donne un petit côté high-tech que j'adore!