hey there i have a dwc set up but i find the girls are thirsty and i have to top up the water every 3 days or so. i was thinking about adding a separate reservoir with pipes going into the DWC to automatically top up the water. my problem is how can i get the pump to turn on and off according to water level instead of putting it on a timer. also i have more than one DWC pot going, would i need 2 separate pumps one to supply each pot? any help would be great.