Hayward Vac problems in Round pool

We have an in-ground 21' round pool that was obviously built by a former home owner who only kind of knew what they were doing. We've done a lot of upgrades and are very happy with it. My wife sprained her ankle so she's not able to vacuum the pool as often as needed so we bought a new Hayward XL.

The problem is that the return from the pump comes in at an angle and with the round pool, after a few minutes the entire pool is spinning counter clockwise. When the vac turns into the current, it doesn't have the power to move against the flow and ends up flipping over. After a while it will right its self and start again until it turns back into the current. Is there an easy way to place something over the outlet that will change the direction of the incoming water? It's coming out with considerable force so it would have to be rather resilient.

Most pool inlets can be re-directed. This image isn't very good, but I have nothing better:
http://lomart-parts.com/images/coleco-return.jpg

Hopefully, it will give you an idea about how to loosen the typical retaining ring, and adjust the eyeball used in most returns.

That's for an above ground pool. Ours is a concrete/plaster in ground. That won't work.

The design is the same, if you have a standard pool inlet. What's usually different is the back half, not the part exposed to view.

Just had a thought -- I have occasionally seen pools build by fly-by-night types, that simply used PVC stubbed out pipes to return water to the pool. If you are unfortunate enough to have that situation, you may be able to INSTALL a proper eyeball return, but otherwise, may find it hard to correct the problem you have.

There is no "back half". It's a hole in the concrete where the water comes out. The pool is at least 30 years old.

There has to be piping in the hole somewhere; concrete as it is installed in pools will erode from continuous flow. Most likely, if you look back in the hole with a light, you'll see the piping.

This is sub-standard construction, so there's no telling how it was done. Without photos of the opening AND down into the hole, I'd have no idea how to correct your problem.