Suspended Solid sensors

Firstly, no SS sensor is ever going to be maintenance free.

What is the process fluid in your tank? Is this for a wastewater treatment plant?

Dear Saffa,

thank you for your reply,
yes it is for wastewater treatment plant.
it can be located in the aeration tank and after the sand filters.

For final effluent you probably need both -the one part appears to be the controller/transmitter and the other appears to be the sensor that is immersed in the process fluid.

This appears to be a turbidity instrument, probably has an output in NTU (Nephelometric Turbidity Units).

The unit named is unlikely to work in the aeration basin, where the solids concentration is several thousand ppm. This is a tough environment, and anything with submered moving parts is doomed to failure in my opinion.

I strongly suggest you contact the supplier(s) for application assistance and direct conversation.