People can make things more complicated than they need to be sometimes.
Not me!
I run a small 50 watt panel to power a small 12 volt pump.
No need a battery, because I am happy that the pump does not run when the sun does not shine.
No need for an inverter because the pump is 12V and runs directly off the panel.
Works just fine. Very Cheap! Very Easy!
Aquaponics pumps need to be off some times to give the
roots some time to get air, so the fact that it does not pump when the sun goes down (or behind a cloud) is just perfect.
I posted a little
video here:
http://youtu.be/aOK5VR2QatU