what kind of batteries does this use?

303/357 Battery - SR44 - Silver oxide 190 mAhModel 357A

What are the recommended and maximum flow rates? PSI?

FROM HM DIGITAL: There are no recommended flow rates, but there is a maximum pressure rating, which is 232 PSI (16 bar) at room temperature (25C/77F).

Can this be dropped into a DWC 5 gallon bucket and left in there so to measure the ppm's anytime i turn it on (since wire is sitting in the water) ?

It should not be fully submerged, only the probe up to the threads should go into liquid. You could probably seal wire end with a conformant coating or silicone though, do NOT get any on probe end. Yes it can be used in a deep water or reservoir, it does need to have some type of consistent flow in the probe area... to give a consistent reading ! ...get it naysayers, please think before you post inaccurate advice. A basic bubbler agitating solution will work. Be sure to locate probe out of direct bubble area , the bubbles will skew results. I've also used these in unagitated tanks , they work...but will only read the general area , obviously. This will give a general, consistent, read for on the fly observations of nutrient solution, but you still need to compare with a true reading for accuracy. TLDR Dont fully trust this as your standard when used for hydro, DO use as a consistent observation guide,check occasionally against a REAL meter/test, and keep it out of bubbles or it'll get wonky readings.

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

Product ID: 254566832

Details

Brand
HM Digital
Item dimensions L x W x H
48 x 20 x 76
Item weight
45 g
Material
Plastic
Number of Items
1

💧0-9990 ppm TDS range

🔋1000 hrs battery life

⚙️2% readout accuracy

¥6736

Duties & taxes included

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Sold byAmazon JapanDelivered byDesertcartCustomer service byDesertcartReturns14 days · 30 with PRO

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Description

💧 Stay ahead of impurities—because your water deserves VIP treatment!

SMART AUTO OFF - Saves battery life by powering down after 10 minutes of inactivity—eco-friendly and efficient.
DUAL INLINE PRECISION - Monitor both tap & purified water TDS simultaneously for real-time purity insights.
EFFORTLESS INSTALLATION - Quick-connect fittings and compact design make setup seamless—no plumber needed.
ADVANCED MICROPROCESSOR TECH - Ensures ultra-accurate readings with 2% precision to keep your water quality in check.
UNIVERSAL FILTRATION COMPATIBILITY - Perfect for RO, DI, and other filtration systems to verify your water’s purity instantly.

The HM Digital DM-1 In-Line Dual TDS Monitor offers precise, real-time measurement of total dissolved solids in water with a wide 0-9990 ppm range and 2% accuracy. Designed for easy installation in filtration systems like reverse osmosis and deionization, it features dual sensors to compare feed and product water quality, a long-lasting battery with auto-off function, and a compact, user-friendly design ideal for professionals seeking reliable water purity monitoring.

Specifications

ASIN	B001EHAZGW
ASIN	B001EHAZGW
Batteries	2 LR44 batteries required. (included)
Best Sellers Rank	#29,641 in Tools & Home Improvement ( See Top 100 in Tools & Home Improvement ) #29 in Moisture Meters
Brand Name	HM Digital
Customer Reviews	4.6 4.6 out of 5 stars (2,680)
Customer reviews	4.6 4.6 out of 5 stars (2,680)
Date First Available	7 August 2012
Global Trade Identification Number	00891144000052
Included Components	Bag
Is Discontinued By Manufacturer	No
Item Dimensions	48 x 20 x 76 millimeters
Item Weight	0.1 Pounds
Item model number	716186
Manufacturer	HM Digital, Inc.
Manufacturer	HM Digital, Inc.
Material Type	Plastic
Model	716186
Number of Items	1
Part Number	DM-1
Product Dimensions	4.83 x 2.03 x 7.62 cm; 45.36 g
Set Name	Dual
UPC	733169337600 891144000052 885169394012 885156810310
Unit Count	1 Count

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