I have just had a 26'x 12' pond dug in clay. I used a liner over that and have slate or flagstone around a 3' wide lip/ perimeter. However, all the grass in the yard is now gone and there is just red clay. Ideally, I think this would be a great time to bring in a truck load of sand to make a beach like environment back there surrounding the pond since grass seed probably won't grow in that red clay.

Do you think it would be OK to put sand over top of red clay as a ground cover in this setup ? Can you forsee any problems with going with sand ? One thing I am looking at is that I really do not want to have to mow that area if I can avoid it and the beachy theme seems beautiful to me. Any input?

I think I may have found an answer to part of the issue of how to protect my pumps from sand. I can also put my pump inside a milk crate covered with a cotton bag to protect it from sand.
https://youtu.be/DTN5Cn3YATo

The only other issue now is whether I need to put down landscape fabric over the clay first. I guess I can avoid that by getting a whole lot of sand (double the intended amount) and calling it a day.

I would put down the fabric, unless bringing in another load of sand 4-5 years down the road and spreading it out won't be a problem.