Marmonix MHM 300 Digital Hay Moisture Meter | High-Precision Probe for Alfalfa & Forage
- Range: 0–80% Moisture Content
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Accuracy: $\pm 0.5\%n$ with Auto-Temp Compensation
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Display: Backlit 4-Digit LCD
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Probes: Long-reach dual stainless steel pins
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Power: 4x AAA batteries with Auto-Off
The Marmonix MHM 300 Digital Hay Moisture Meter is a high-tech testing instrument specifically engineered for the modern agricultural industry. In the world of hay production, moisture control is the single most important factor in determining crop quality, storage safety, and market value. The MHM 300 provides farmers and ranchers with a reliable, scientific method to monitor moisture levels, effectively eliminating the guesswork that leads to mold growth or spontaneous combustion in stored bales.
Precision Engineering of the MHM300
The MHM300 utilizes the sophisticated relationship between moisture content and electrical resistance to deliver instantaneous, high-resolution data. This Marmonix MHM-300 is equipped with a robust dual-probe system designed to penetrate deep into tightly packed bales. By measuring the electrical conductivity between these stainless steel sensors, the MHM 300 translates complex resistance data into a clear, digital percentage on its 4-digit LCD.
Versatile Calibration for Multiple Hay Types
One of the standout features of the MHM_300 is its extensive calibration range. This moisture analyzer is optimized for a wide variety of hays and forages, ensuring accuracy across different plant structures and densities, including:
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Alfalfa and Clover: High-value leguminous crops requiring strict moisture oversight.
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Leymus Chinensis: Frequently used in professional livestock feed.
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Orchard Grass: A staple for high-quality equine forage.
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Pennisetum Hybridum (Napier Grass): And other heavy-stemmed tropical grasses.
Advanced Technology in the Marmonix MHM 300
Field conditions are rarely perfect, which is why the MHM-300 is built with Automatic Temperature Compensation (ATC). Environmental heat can often skew electrical resistance readings; however, the MHM300 automatically adjusts its calculations based on the ambient temperature (ranging from 0–60°C). This ensures that whether you are testing in the cool damp of the morning or the heat of a summer afternoon, your data remains consistent.
Ergonomic and Durable Design of the MHM_300
The physical build of the Marmonix MHM-300 is as impressive as its software.
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High-Visibility LCD: The MHM 300 features a backlit display, allowing for effortless reading in dark barns or under the high-glare conditions of an open field.
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Ultra-Lightweight Portability: At only 203g, the MHM300 is easy to carry through large fields or across multiple haystacks without fatigue.
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Smart Power Management: To preserve the 4×1.5 AAA batteries, the MHM-300 includes both manual and automatic power-off functions.
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Long-Reach Probes: The 460mm dimensions ensure you are measuring the moisture at the core of the bale, not just the surface.
MHM-300 / MHM 300 / MHM300 Technical Specifications
| Specification Feature | Technical Details |
| Primary Model | Marmonix MHM-300 |
| Search Variations | MHM 300, MHM300, MHM_300 |
| Measuring Range | 0% – 80% Moisture Content |
| Accuracy Rating | $\pm 0.5\%n$ |
| Resolution | 0.1 |
| Operating Temperature | 0°C to 60°C |
| Operating Humidity | 5% to 90% RH |
| Method of Operation | Electrical Resistance (Probe Method) |
| Power Supply | 4 x 1.5 AAA size (UM-4) Battery |
| Total Weight | 203g (Excluding Batteries) |
| Dimensions | 460mm × 75mm × 35mm |
| Manufacturer Guarantee | 2-Year Warranty |
Downloads
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We’ve tested several brands, but the NETD 70mK sensitivity on the MTV256 PRO makes spotting slight moisture variations behind drywall incredibly clear.
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The MTV_256 PRO works exactly as described, but the user manual was missing from my box. Had to figure out the menu settings on my own.
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The thermal imaging works great on the MTV-256 PRO, but it takes a little longer to boot up than my older, lower-res camera. Still a good tool.
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Dave R. –
The -20 to 400C range is perfect for industrial mechanics. The MTV256 PRO holds its charge well, getting a solid 4 hours of use as advertised.
ohn S. –
I’ve been baling alfalfa for 20 years and this MHM-300 is one of the best testers I’ve used. Probes go deep into the square bales.
Sarah Jenkins –
Lifesaver! Bought the Marmonix MHM300 to make sure our horse hay wasn’t too damp before storing. Super easy to use.
Mike T. –
Good solid unit. The MHM 300 reads fast and the backlit screen is great when I’m checking bales in the barn at dusk.
T. Wallace –
Finally a moisture meter that doesn’t drain batteries in a week. The auto power-off on the MHM-300 is a great feature.
Pete –
Works okay for the price. The probes on the MHM 300 are sturdy, but I wish it came with a hard carrying case instead of just the box. Still gets the job done.
K. Peterson –
We run a large dairy op and use the MHM300 daily during the summer. Spot on accuracy on our orchard grass.