Grobo recommends that you use Reverse Osmosis (RO) or Distilled water to keep your plants happiest.
This is for a few reasons:
- Local municipalities have added compounds in the tap water that plants don’t use, like chloride
- RO and Distilled water is less hard and has less salt content - providing optimal conditions for your plant to grow
Note: You can use tap water and the Grobo will adjust dosing level as much as it can, but it is not recommended.