So I got some more questions about these indexing valve things so I figured I should go ahead and write a bit more about them. They may not be appropriate for every situation but they do have their place.
Want to sequence the flow of water into your grow beds to only flood one at a time? Want to avoid extra wiring and control electronics? Then consider an aquaponics indexing valve. All that is needed to operate this valve is a flow of water that starts and stops. If you are already running with a pump on a timer, then each time the pump stops then starts again, the water will be flowing to a different outlet. This is a way to add more grow beds without needing to expand fish tank or sump tank space.
The valves come in three different sizes. 1", 1 1/4", 1 1/2" They also come in a few different bodies. 4 outlets, 6 outlets, 8 outlets (only in 1" though)
There are cams that can be installed in the valves to allow them to operate different numbers of outlets.
For example the 4 outlet body can be cammed to run 2, 3 or 4 outlets and one would simply cap off the unused outlets if any.