YSI Pro30

No — it measures conductivity and temperature, then calculates salinity and TDS from those two readings using the algorithms in Standard Methods.

Yes. The meter and cable are ordered separately, and the conductivity/temperature sensor is part of the cable, so a cable is required to take a reading.

Choose a cable that comfortably reaches your deepest sample point — Fresh By Design stocks 1 m and 4 m, with 10 m, 20 m and 30 m available on request.

Yes — 1 m and 4 m cables read to ±1.0% of reading or 1.0 µS/cm, while 10 m, 20 m and 30 m cables read to ±2.0% of reading or 1.0 µS/cm.

Yes for specific conductance, using a default coefficient of 1.91%/°C referenced to 25 °C, and both the coefficient and reference temperature can be adjusted.

The Pro30 stores 50 data sets in a reviewable memory, which suits spot checks rather than continuous logging.

Both are 4-electrode conductivity meters — the Pro30 adds a longer warranty, more cable length options, a backlit graphic display and a tougher military-spec build, while the EC300A is the lower-cost option for routine checks.