Seems like a no brainer if it works.

If so, how much, which one?  Can you keep your water filtered without any electric?

This is one solar thing I think could actually pay for itself if it exists.

Are you talking about a solar water heater? Or just a pool pump powered by solar panels?

If you're wanting to keep electricity usage down when it comes to a pool pump... just get a variable speed pool pump.

IIRC... non-variable speed pumps over 1HP are no longer legal for sale anymore. Not a fan that the government takes that choice away from people, but the choice to get a Variable Speed pump is legitimately the better option.
My house, when I bought it, had a pool that was left empty... pool pump missing, and wrong sized filter for the pool.
Had to have my pool replastered, and new pool pump and filter put in.

Went with variable speed pump. I dont think the pool pump made hardly any noticeable difference to my electric bill.
If I had gone with a non-variable speed pump, my electricity bill would have increased substantially.

The only downside to a variable speed pump, is the upfront cost is more expensive. But you'll make that money back in saving electricity fairly quickly. Buying a non-variable speed pump is penny wise but pound foolish.

I can't speak on Solar water heaters... but I heard at best it might add an additional month at both ends of the season. Meaning you might be able to start swimming a month early, and keep swimming a month later at the end of pool season. I could be wrong and it might not even be that good.

Thanks for the informed response.

I was thinking of a pump itself that just ran off solar panels with no battery bank needed.  A friend of mine has a well pump that does not need a battery bank at his ranch for a water tank for cattle.  I thought what a great way to run your pool.  It could be on the entire time there was enough sunlight to run it.  Zero cost after purchase and install (until it breaks).

I do have a variable speed pump.

I'm interested in this too, and if diy options are worth it.

You could have a secondary circulating pump that is solar which would just move water through the filter.  But you would still need a second pump to run any features on the pool (cleaning system, spa, water features, water circulation, etc.).  You would also need the pool equipment very close to the pool, distance & any turns really eat up how effective the pump is at moving water.  That added cost of a second pump (along with plumbing), would eat up the electric savings pretty quickly.  By the time it paid for itself, it would be about the time to replace it.

A variable speed pool pump uses a lot of electricity at startup to prime and pull the water through the system.  Without a battery or large panels, solar will not have enough power for a pool pump at startup or at full speed.  At low speed, while circulating the pool, solar could easily do it as a variable speed pump isn't drawing much electricity.  Startup, cleaning cycle (running pool vac or infloor), or running a water feature/spa, it will draw a bunch of electricity and is something you do on a regular basis.  The pump runs at 3500 rpm at startup and goes down to 2500 rpm when cleaning.

Really, adding solar to the house and using that to power it is the answer.  None of the big 3 pool equipment manufacturers (Hayward, Jandy or Pentair) will make such a limited use product like a solar pump.  So it would be a DIY setup.  Between LED lights and variable speed pumps, pools don't use that much electricity.  I haven't measured it, but I have not noticed a significant change in my electric bills since building my pool 2.5 years ago.  Everything, except the heater, is ran every day.  It cleans overnight (midnight to 6am), the spa spillway runs from 7am until 11am, then the pool circulates from 11am until 2pm.  My lights are on from 5pm until 9:30pm and my water features run from 4pm until 8pm.  I want to say there is a $30-40 per month difference at most.  I spend more on gas heating my spa than I do on electricity.

The biggest savings in electricity that I have noticed is replacing old A/C units.  I did that 2.5 years ago and notice a $100 per month (during summer) difference before/after.  I realize as the A/C units start to fail, they short cycle (run more often).  But it was a dramatic difference.      

Thanks for all the knowledge and time spent responding to my question.

Much appreciated.