On the deep end of my pool is a built in bench. There are two ports there which i assumed was for massaging your back. On the pool deck just behind this area are what appear to be two copper lines that were cut off. When i open the valve that turns on the ports at the bench, it sucks air in through one of the cut off copper pipes and blows a lot of bubbles and a little bit of water out of the one port in the water. The other port seems to have nothing coming out of it. I'm confused as to what this is supposed to be or what it used to be.

