Yes anything is possible if the can build a circuit board to power the TDS probe and then get the output voltage converted to the same range as a normal pH or ORB probe hooked up to the GHL . Then the GHL probe input will think it’s a normal pH probe:
Not really very practical idea as TDS readings don’t vary much from Zero if the equipment is Being maintained.
Constant testing is really not needed but as I said it is possible if you have the skills.