The valve is shaped like the letter "T". On the red handle there is a sticker with a "T" on it. When the "T" on this sticker is aligned with the valve itself, the flow of water is coming half from the skimmer and half from the floor drain and going to the pump. The points on the sticker point to what is open in the valve. By turning the handle you can adjust the flow or shut off more suction from the skimmer if you notice a lot of floating debris. You may want more water drawn from the floor drain to reduce the amount of vacuuming necessary. You can shut the flow of water going to the pump off if you need to service the pump or tank.

When sweeping your pool turn the handle so that it is pulling only from the skimmer. This will give you the most suction for your vacuum attachments.

When making adjustments to the T-valve, turn off the pump to prevent any possible damage.