Can I measure water or chemical mix going into the tank more accurately?

Goldacres offer a digital fill flowmeter with optional shutoff valve this flowmeter is mounted permanently on the sprayer and also provides a digital readout of the quantity of water pumped, it can be programed to shutoff automatically when it has reached a pre-set quantity.

Batchmate: A further option for filling sprayers is the Goldacres Batchmate which is a bulk mixing and transfer station of 800L capacity.