Growing plants manually with the water bottles takes twice as much ice compared to when you use the water tank.
Each water bottle needs two ice to craft, rather than just one which is likely the cause of the mismatch.
Additionally, if you pour water bottles on a seed which is being fed from the water tanks, the water is simply lost. The tanks continue draining, and the soil goes dry as soon as the tank runs out.
Related suggestions:
- You should be able to pour water bottles into the tank for 60 units of water.
- If an ice usage would put a tank over capacity, see if there is another tank in the base which can take the overflow instead of allowing it to go to waste.
- If the ice cannot fit then the action should fail. Right now you are able to add ice to a full tank, and the only effect is losing your ice.