MicroTOL Online Turbidimeter for Turbidity Testing

35 years of optical measurement expertise has allowed HF scientific to become a leader in regulatory reporting turbidimeters. The HF scientific MicroTOL Online Turbidimeter has been specifically designed to meet regulations of the EPA and ISO 7027. Features include fast and easy calibration, verification in seconds, low maintenance, fail safe design which ensures your instrument is always reading accurately, bubble rejection system, automatic continuous ultrasonic autoclean system (except MicroTOL #2 & #5 models), and a data acquisition software system that allows logging and data storage for multiple turbidimeters.

No need to monitor turbidity greater than 10NTU?

HF scientific has added four new low range models, the new 0.02-10NTU models #5 (White light and IR) and 0.02-10NTU models #6 (White light and IR) that are perfect for applications such as drinking water where a measurement range greater than 10NTU is not needed. Calibration points are 0.02, 1.0 and 10NTU.


  • Fast and easy calibration

    Verification in seconds while a complete primary calibration can be completed in less than 5 minutes

  • Low volume sample chamber
    Low volume sample chamber (30ml) reduces calibration costs and provides quick response times

  • Low maintenance fail safe design
    Simple modular design - Easy to use and service

  • Bubble rejection system
    Eliminates bubbles without delaying the response time

  • Affordable
    Modular microprocessor based technology ensures high quality at the industry's lowest price

  • Autoclean (except MicroTOL 2 and 5)
    Automatic continuous ultrasonic autoclean allows for the first EPA 180.1 accepted automatic cleaning online turbidimeter

  • Made in the USA

Optional Features

  • Online software

    Allows logging, comparisons, graphs and data acquisition for multiple online turbidimeters into a PC

  • Remote display
    Allows remote monitoring up to 500 feet away


Measurement principle Nephelometry (90°)
Range Auto ranging from 0.02-10, 0.02-100, and 0.02-1000 NTU depending on model
Resolution 0.0001 Selectable
Accuracy 2% of reading or ±0.02 below 40 NTU (0-500 NTU)
5% of reading above 40 NTU (500-1100 NTU)
Response time Adjustable (5 to 500 seconds) 0 to 1000 NTU
Standard outputs 4-20 ma galvanic isolated or RS-485
RS-485 protocols Modbus, HF simplebus, HF Online interface
User alarms 2 user selectable high/low alarms
Light source White light or infrared (850nm LED)
Operating temperature 0°-50°C (32° to 122°F)
Input pressure 1 - 200psi (built in regulator set at 15psi)
Enclosure NEMA 4X, IP66
Display Multiline custom LCD (backlight option)
Certifications USEPA, ISO 7027, CE approved, ETL Listed to UL 3111-1 and ETL certified to CSA 22.0 No. 1010-1-92


Literature and Specifications
Operators Manual

Chlorine Pocket Photometer Instruments and Accessories


Model Description
20053 MicroTOL 2 instrument, white light , 0 - 1000 NTU
20054 MicroTOL 2 instrument, Infrared , 0 - 1000 NTU
20055 MicroTOL 3 instrument, white light , 0 - 100 NTU, Autoclean
20056 MicroTOL 3 instrument, Infrared , 0 - 100 NTU, Autoclean
20063 MicroTOL 4 instrument, white light , 0 - 1000 NTU, Autoclean
20064 MicroTOL 4 instrument, Infrared , 0 - 1000 NTU, Autoclean
40060 MicroTOL 5 instrument, white light, range 0.02-10 NTU
40061 MicroTOL 5 instrument, Infrared, range 0.02-10 NTU
40070 MicroTOL 6 instrument, white light, range 0.02-10 NTU with ultrasonic autoclean
40071 MicroTOL 6 instrument, Infrared, range 0.02-10 NTU with ultrasonic autoclean


Model Description
02053 Electronic service module MicroTOL 2 WL (also will retrofit to MicroTOL 1 WL)
02054 Electronic service module MicroTOL 2 IR (also will retrofit to MicroTOL 1 IR)
02055 Electronic service module MicroTOL 3 WL
02056 Electronic service module MicroTOL 3 IR
02063 Electronic service module MicroTOL 4 WL
02064 Electronic service module MicroTOL 4 IR
19778 Inline flow regulator (1L/min) Recommended for pressurized system
19787 Converter RS-485 to USB. For use with HF Online Software
19945A Flow Alarm for MicroTOL (factory installed)
20106 Stilling / Bubble Removing Chamber
20111 24 volt Power Supply for MicroTOL (factory installed)
20779S Power Cord 120VAC
20815 22 gauge RS-485 two wire twisted pair shielded communication cable (sold per foot)
21045A Inductive Isolator Option for 4-20mA
21201 Source/Drain Tubing - sold per foot
21201S Source/Drain Tubing - 50 foot roll
21396S Lamp assembly for infrared models
21555R Replacement Desiccant Pouch
24017S Junction Box Power Supply Assembly
24082S Lamp assembly for white light models
24165S Flow through assembly, nylon (does not include cuvette)
24166S Ultrasonic cuvette assembly - MicroTOL 3, 4 and 6
24306S Inline pressure regulator
39824 ProCal Primary Calibration Standard - 100 NTU
39825 ProCal Primary Calibration Standard - 10 NTU
39950 ProCal Primary Calibration Kit - 0.02, 1.0 and 10 NTU (for MicroTOL 5 and 6)
39953 ProCal Calibration Kit .02,10, and 100NTU (for MicroTOL 3)
39957 ProCal Primary Calibration Kit, Full Range, .02, 10, and 1000 NTU (for MicroTOL 2, 4 and Micro100)
50036 Flow through cuvette - MicroTOL 2 (3 pack)
50040 Formazin Stock Solution Kit - Primary Calibration - each kit contains: 32 onces of 4000 NTU Formazin, one gallon 0.02 NTU Reference Standard, four cuvettes with indexing light shields, three pipettes and instruction manual
50121 Flow Through Assembly, high temperature, 0 - 90°C (32 - 194°F)
50125 Flow through assembly (includes non ultrasonic cuvette)
70914 Formazin Stock Solution - 4000 NTU in a 16 oz bottle
98877 Demo Stand for MicroTOL


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