Hanna HI 991404 - Low Range pH/EC/TDS/Temp Monitors

Hanna HI 991404 - Low Range pH/EC/TDS/Temp Monitors


  • Waterproof
  • Adjustable TDS ratio and adjustable
  • Stability indicator and HOLD

This indicator continuously monitors the three most crucial nutrient parameters in hydroponic, greenhouse and horticultural applications.

At startup, HI 991404 performs a self-check to assure proper working condition. The stability indicator and HOLD function lets the user know when to take readings and freezes the reading on display for easy and accurate recording.

This instrument is supplied with a non-clogging double junction pH electrode as well as a rugged conductivity probe that will withstand even the most aggressive environments. The 12 VDC adapter makes these instruments ideal for all continuous monitoring applications.


pH 0.0 to 14.0 pH
EC 0 to 3999 S/cm
TDS 0 to 2000 mg/L (ppm)
Temperature 0.0 to 60.0C / 32.0 to 122.0F

pH 0.1 pH
EC 1 S/cm
TDS 1 mg/L (ppm)
Temperature 0.1C (0.1F)

pH 0.1 pH
EC/TDS 2% F.S.
Temperature 0.5C (1F)

Temperature Compensation
pH - Automatic, one point or two points with auto buffer recognition
EC/TDS - Automatic, with adjustable from 0.0 to 2.4%/C

pH - Automatic
EC/TDS - Automatic, one point at 1413 S/cm or 1382 ppm

TDS Factor:
Adjustable from 0.45 to 1.00

0 to 50C (32 to 122F); RH max 95% non-condensing

Input Impedence:
1012 Ohm

Power Supply:
12 VDC adapter (included)

160 x 105 x 31 mm (6.3 x 4.1 x 1.2) / 190 g (6.7 oz.)

ph - HI 1293D PEI body, pre-amplified pH electrode with 1/2" NPT pipe thread, DIN connector and 2 m (6.6') cable (included)
EC/TDS - HI 7630 conductivity probe with 1/2" NPT pipe thread and 2 m (6.6') cable(fixed)

Item Number: 131910
Manufacturer: Hanna Instruments
Manufacturer's Part Number: HI 991404


pdf file Instruction Guide
pdf file Instruction Manual

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