Water timer

[Black Phantom]

Probably the cheapest way is to buy a humidifier float kit from Home Depot and then install it in your bucket. A single hole drilled in the side is all you need to do and then run a separate RO line into it. I did this with my 45 gallon containers and it works just fine. You just need to scale it down some. They are less than $20 bucks if I remember correctly.