The idea of a solar powered pump comes up in this channel frequently. In
this case, your questions seem to be related more to pump recommendation
then about the solar power. I personally like pumps from the little giant.
http://www.lgpc.com/

As the solar power issue, here are some things to consider. Solar panels
generally produce about 12vdc. 12vdc pumps aren't designed for continuous
duty. So you'll need an inverter to produce 120vac, and possibly a battery
rack to power the system when the sun isn't shining.

The biggest problem with solar powered pump systems is that the biofilter
needs actively flowing water to work, and it quickly dies from lack of
oxygen when the pump is off. Plus the oxygen levels in the pond decline at
night, as plants consume oxygen instead of producing it, quick further
justifies the need for water circulation at night.

But if you can run the numbers and save money by running it off solar in the
day time, I'm all for that.

-S