Thanks, Simon. I am a shrimpnewb after all. My tank has pretty much zero evaporation - it's weird, but it seems to have something to do with not running a heater and the water temperature being the same as the room. I'm just planning to switch over to the shrimp focused mineralizer with water changes over time. I'll update the TDS differences I assume will be there.
This has got rather long and involved, interesting though!
Just wanted to remind you that topping up tanks from evaporation will still need pure RO water (not mineralised) though so you will need to keep some Pure RO water aside for that.