20x40 Inground Poo, vinyl liner

Just had new work done around the pool they used polymeric sand which trickled down the wall of the pool and accumulated where the wall and the bottom meet. Now I have been able to vacuum most of the bottom clean, but where the polymeric sand has accumulated, I can't vacuum that up. Almost as if it has solidified. Polymeric sand's bonding ability is activated by water and I am not sure how solid that is down there. It's too cold to go in and check. Any ideas on how I could break it free of the wall? The cheap pool extension pole cannot apply enough pressure with the brush to break it up. I was thinking of putting a long power wash wand on a piece of rigid PVC pipe to see if that would break it up. But I am looking for better ideas. I was told it would brush off with a firm brushing but like I said I can't get enough pressure.

Looking for advice on how to break this stuff up so it will vacuum out.

Any ideas?
Thanks
Ray