Conductivity Probe K 0.1

Atlas Scientific Conductivity EZO-EC get what you pay for

Some nice supporting software and literature, and relatively cheap in the field, but some rough edges. The carrier board is not ideal for I2C and doesn't work to ESP32 with strong pull ups as unable to pull ACK low enough. Changing the IC to a proper open drain I2C isolator resolved this. The biggest issue is the software fails if probe goes out of range (eg solution too saline for probe). It comes back "pending" to the reading, and for ever more even to queries as to who it is! Until you power cycle. Atlas Scientific do not see this as an issue as expect the probe to be selected for the expected range to be encountered and have no plans to fix. Other than that, seems "ok".

Atlas Scientific's quality

Not much to add... Expensive but worth every penny. Anything cheaper can't be relied on professionally and ends up costing infinitely more.

Good experience

The probe works as expected. We had a straightforward discussion about purchasing, and once I knew I wanted the probe, everything worked well and quickly. Overall, it was a good experience.