The pHotoFlex line of colorimeters is the newest addition to YSI's full range of colorimeters. These rugged, waterproof, multiparameter colorimeters are ideal for laboratory and field testing.

Receive 20 free packets of DPD Free Chlorine or DPD Total Chlorine! Get your free samples. Interested in a pHotoFlex colorimeter? Learn about the trade in program currently going on (U.S. only). Or, if you prefer to buy from one of our dealers, take advantage of our rebate program!

The instruments feature a large, backlit display, waterproof rating, data logging with the ability to export data to a computer using LSdata software, user-defined programs and a 2-year warranty.


Model pHotoFlex STD (colorimeter only) and Model pHotoFlex pH (colorimeter with pH electrode capability) feature:

  • Calibration adjustment for selected methods
  • Data storage; 100 data sets with pHotoFlex STD and 1,000 data sets with pHotoFlex pH
  • Large, easy to read backlit LCD display
  • IP-67 waterproof case; easy to hold or set on a benchtop (lab station also available)
  • Flexible, fixed adapter for various cell types features a flip design to accommodate a variety of heights and diameters; it is also attached to prevent it from being lost
  • ~138 parameters (pHotoFlex pH); 85 parameters (pHotoFlex STD) - reagents can be used on YSI colorimeters or any other brand
  • PC connectivity to manage data (optional LSdata software) and update firmware or methods; barcode compatibility
  • pHotoFlex pH offers a BNC connection in order to take pH measurements directly and to measure the pH dependent parameter NH3

​pHotoFlex pH/SET or STD/SET Includes the pHotoFlex pH or STD colorimeter with the above features but also comes in a convenient kit:

  • field case with field tray
  • vials
  • pH electrode (with pH/SET)
  • 2 each 10 mL and 2 mL syringe
  • empty cuvettes 16+28 mm
  • cleaning tissues
  • stand
  • 2 empty buffer bottles
  • beaker
  • screw driver
  • PC-software LSdata
  • and RS232 PC cable

If you are interested in measuring chlorine or COD only, you might be interested in our single parameter colorimeters, YSI 900 Chlorine and YSI 910 COD.


SKU: 251205Y

pHotoFlex pHotoFlex Colorimeters: Certifications ETLus, cETL, IP67 waterproof, CE
Connectivity / Communications RS232
GLP Compliance Yes
Measurement Range Absorbance: -0.200 to 2.000 Transmission: 1 to 150%
Memory Yes, 100 data sets
Parameters Measured A wide variety of YSI pHotoFlex Colorimeter Reagents. See specifications.
Power ~3000 measurements, Four 1.5 V AA alkalines
Unit of Measure mg/L
Warranty 2-year instrument
Waterproof Yes

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