A rolling ball water fountain is a deceptively straightforward design. Much of the basic water fountain rules apply, except that in this case, you are setting up the flow of water to support a spinning marble ball. This will require a more powerful pump than on a standard tabletop fountain. With these variations in mind, assembling a rolling ball fountain is fairly straightforward.
Place the water pump at the bottom of the bowl and attach the plastic tubing to the pump outlet.
Test the water flow of the pump by filling the bowl with water and plugging the electrical cord of the pump into an outlet. Set the water flow control to high to create the rolling ball effect. Verify that the pump is set to high and in good working order.
Feed the plastic tubing from the pump outlet through the drilled hole in the rock base. Cut the plastic tubing so that it is flush with the top of the rock base and is not visible from the exterior.
Test that the water flow is powerful enough to roll your marble ball when placed on top of the drilled hole on the upright rock base. If your test is unsuccessful, replace your pump with a pump that has a higher gallon per hour capacity.
Remove the water and the rock base from the bowl and begin construction by placing the pump at the bottom of the bowl.
Cut two holes into the sides of the plastic container: one for the electric cord and the other for water intake for the pump.
Cut a hole at the top of the plastic container to accommodate the plastic tubing.
Place the plastic container over the pump and thread the plastic tubing and the electrical cord through their designated holes.
Fill the base of the bowl around the pump and protective plastic covering with large river stones, making sure not to cover or crowd the water intake hole.
Feed the plastic tubing from the pump outlet through the drilled hole in the rock base.
Place the rock base level over top of your ceramic bowl and fill in any holes with river rocks.
Fill the bowl with water and plug in the electrical cord for the pump.
Place the marble ball over the water bubbling from the drilled hole of the rock base.
When purchasing your supplies verify that the plastic tubing is narrow enough to fit through the hole in your rock base. Fountain supply stores are the easiest places to find materials for this project, including predrilled rock bases.