pipes from skimmer to pump

[warren]

as a novice I do not understand why there are two pipe, rather than one pipe, running from skimmer to pump, and why closing the valve on one
of them, as opposed to the other, allows me to vacuum the pool through
the skimmer fitting.

Can anyone briefly explain the plumbing architecture here?

thanks,

warren

[Denali]

The two lines are for the skimmer and the main drain. If both run back to the pump when you can control how much suction comes from each.

Another setup is two lines but only one going back to the pump. The main drain line comes up to the skimmer. The skimmer line goes to the pump. Control of flow is done with a valve at the bottom of the skimmer.

as a novice I do not understand why there are two pipe, rather than one pipe, running from skimmer to pump, and why closing the valve on one
of them, as opposed to the other, allows me to vacuum the pool through
the skimmer fitting.

Can anyone briefly explain the plumbing architecture here?

thanks,

warren