Discontinued Products & Recommended Replacements

YSI products are built to last (just look at the model 58!).  Eventually there comes a point where new technology and innovation provides better features and benefits and those trustworthy meters are retired.  

Here's a listing of the products we've developed over the last 60 plus years that have served us well but are now discontinued.  We've provided a suggested list of product replacements to help in your search.

If you have one of these discontinued meters and need a manual for it, check the listing near the bottom of this page.

Product Replacement
30 Conductivity Meter EC30A, EC300A, Pro30
31 Conductivity Bridge 3200, 3100
31A Conductance Bridge 3200, 3100
32 Conductance Meter 3200, 3100
33 S-C-T Meter EC300A
34 Conductance-Resistance Meter 3200
35 Conductance Meter 3200, 3100
50 Dissolved Oxygen Meter ProSolo, Pro20, Pro20i, DO200A
50B Dissolved Oxygen Meter ProSoloPro20Pro20i, DO200A
51 Oxygen Meter ProSoloPro20Pro20i, DO200A
51A Dissolved Oxygen Meter ProSoloPro20Pro20i, DO200A
51B Dissolved Oxygen Meter ProSoloPro20Pro20i, DO200A
52 Oxygen Meter
(1960's version)
ProSoloPro20Pro20i, DO200A
52 Dissolved Oxygen Meter
(2000's version)
ProSolo, Pro20, Pro20i, 58
54ARC and 54ABP Dissolved Oxygen Meters ProSolo, Pro20, Pro20i, DO200A
55 Oxygen Monitor
(1960's version)
ProSolo, Pro20, Pro20i, DO200A
55 Dissolved Oxygen Meter ProSolo, Pro20, Pro20i, DO200A
56 Dissolved Oxygen Monitor ProSolo, Pro20, Pro20i, DO200A
57 Dissolved Oxygen Meter ProSolo, Pro20, Pro20i, DO200A
Product Replacement
59 Dissolved Oxygen Meter ProSolo, Pro20, Pro20i, DO200A
60 Handheld pH Meter pH10A, pH100A, Pro10
63 Handheld pH, Conductivity Pro1030
80 Laboratory Recorder None
80A Single Channel and Model 81A Dual Channel Laboratory Recorders None
85 Handheld Oxygen, Conductivity, Salinity, and Temperature System ProQuatro, Pro2030
91 Dew Point Hygrometer None
95 Handheld Dissolved Oxygen ProSolo
550 Handheld Dissolved Oxygen Meter ProSolo, Pro20, Pro20i
550A Handheld Dissolved Oxygen Meter ProSolo, Pro20, Pro20i
556 Handheld Multiparameter Instrument ProQuatro, ProDSS
1500 Sport Lactate Analyzer None
2300 Stat Plus Glucose/Lactate Analyzer 2900D Biochemistry Analyzer
2700 Select Biochemistry Analyzer 2900D Biochemistry Analyzer
2700M Online Monitoring & Control System 2900M Online Monitoring & Control System
3100 Conductivity Instrument MultiLab
3200 Conductivity Instrument MultiLab
5200 Recirculating System Monitor 5200A
5300A Biological Oxygen Monitor System None
Product Replacement
600QS EXO1
600R EXO1
600XL EXO1
600XL-V2 EXO3
600XLM-V2 EXO3
610 Display/Logger EXO Handheld
610D / 610DM Display Logger EXO Handheld
650MDS EXO Handheld
3000 T-L-C 600LS, CastAway™ CTD
3560 Water Quality Monitoring System ProQuatro
6000UPG Multi-Parameter Water Quality Monitor Multiparameter Sondes
6200 Data Acquisition System Systems Integration
6500 None
6600 EXO2
6820 EXO3
6920 EXO3
6920DW, 600DW None
7100 Multiparameter Bioanalytical System 2950D Biochemistry Analyzer
8500 CO2 Monitor None
9600 Nitrate Monitor None
ADV6600 Environmental Monitoring System EXO2, SonTekADV
BODAnalyst Software BOD Analyst Pro™
EXO Handheld, 1st Gen  EXO Handheld
PC6000 Software EcoWatch Software
ProODO ProSolo
Professional Plus ProQuatro, ProDSS
SondeCom Software for Palm OS None
WaterLOG H-3553T Bubbler Amazon Bubbler
WaterLOG H-3551T Bubbler Amazon Bubbler

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The Ultimate Sampling Handheld. Portable Meter for DO, Conductivity, Salinity, TDS, pH/ORP, Turbidity, Algae, Temperature and more

$2,053.50 - $2,701.50

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Pontoon Vertical Profiling System

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ProSolo Optical Dissolved Oxygen Meter

Portable Optical Dissolved Oxygen, Conductivity, Salinity, and Temperature Digital Handheld Meter


2900M Online Monitor & Control System

Two Chemistry Online Monitor & Control System

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MultiLab 4010-3W

Three channel benchtop multiparameter instrument with wireless capability


HYCAT Autonomous Surface Vehicle

Autonomous Surface Vehicle

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Amazon Bubbler

Self-contained Continuous Flow Bubbler with Fully Integrated Pressure Sensor

$4,103.00 - $4,464.00

IQ SensorNet Alyza Analyzer PO4

IQ SensorNet Orthophosphate Analyzer

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