You didn't mention what if any type of medium you are using. Submersible pumps are designed to drain back through the
pump when they shut off.
You can water every so often if you are using a medium to hold a little moister between waterings. If you aren't using a medium then you do have to run the pump continuously and putting an air bubbler in your tank is one of the best things you can do.
Maybe gourd plants don't like that much water.