Never seen a setup like this. My pool, installed by the previous owner, does not have a separate PVC suction line from the main drain to the pump. One of the skimmers, the one closer to the pump has two holes in the bottom. One of them is the draw from the main drain and the other is the suction to the pump. In theory, I am able to rotate the skimmer basket to select skimmer, main drain, or both. The bottom of the skimmer basket isn't flat. Half of the round basket is lower than the other side and apparently can be rotated to block the main drain or to open it up. I've never seen this.
As a result, there is no rotating isolation valve before my pump that I had in my previous pool that most of us are used to.
Anyone ever see a setup like this and who makes those baskets, in case I break one?
Anyone know if this setup is effective?