EQUIPMENT AND SUPPLIES--Hydrolab #4041


In Reply Refer To:                            May 28, 1982
EGS-Mail Stop 412



QUALITY OF WATER BRANCH TECHNICAL MEMORANDUM NO. 82.14

Subject: EQUIPMENT AND SUPPLIES--Hydrolab #4041

A problem involving inaccuracies in pH measurements made with 
the Hydrolab #4041 digital water-quality meter has been 
identified and attributed tentatively to the reference 
electrode circuit. Until further notice, the Hydrolab #4041 
digital unit should not be used to measure pH. All other 
Hydrolab instruments use different pH electrodes and may be 
used with confidence. You will be notified of corrective 
measures deemed necessary as soon as the problem has been 
rectified.

Herman Feltz is working closely with Hydrolab personnel to 
solve and correct the problem and this should not take long. 
Please do not contact the Hydrolab Company regarding the 
problem. Address all inquiries to Herman Feltz or the Quality 
of Water Branch.



                        R. J. Pickering
                        Chief, Quality of Water Branch

This memorandum does not supersede any previous memorandum.

Key Words: Water quality, equipment, instruments, meters

WRD Distribution: A, B, S, FO, PO