There are comment as below on the datasheet.
"ADM3483/ADM3488 are more tolerant of imperfect termination."
Is this meaning the termination resistor is not required?
This is nice work modifying the CN0359 code to send conductivity data as response to a command through RS485.
I think the issue, however, is with the RS485 communications. The CN0359 uses the ADM3483 which doesn't have true fail-safe receiver…