Suction & return line valve questions

[entendu]

So here's my valve setup:

The upper is suction, the bottom is return, yes? Now, I see on the suction side there are two pipes, one is for the 2 skimmers and one is for the main drain?

On the return side, why are there two pipes, and why is one side shut off? I have 2 eyeballs, both are running in this position. There's a pressure line for a cleaner (I'm using a robot instead), is it for that?

Guess I need to try it out, just don't want any nasty surprises

 

[YippeeSkippy]

Yes, that is how my pool is set up also. On the pressure side I can turn valves to direct more or less pressure to either the eyeball returns or the cleaner return. If I have too much pressure going to the cleaner return the polaris will tip over... so I tweak these valves.

And my skimmers are able to work independently from the main drain.
The MOST important thing to remember is to never shut off both skimmer and main drain at the same time or you'll starve the pump. When I used to vacuum from the skimmer I would decrease the suction or close the main drain line so as to increase the pull from the skimmer.

 

[entendu]

Closing the main drain while vacuuming -- now THAT'S a good tip! Was wondering why the vacuum seemed kind of lame...