Add a post process material effect to a post process volume?

I’m using post process volumes to handle how my water looks when the player is swimming. I want to add a ‘ripple’ effect to the view when underwater.

I’ve created the material but can’t see a way to use it in the post process volume. Can this be done?

Thanks

I ended up simply adding a node to the world post process chain, and toggling it through script when the player’s head goes under/above the water surface.