Valve between skimmer and pump found halfway closed. Why?

[FailedChemistry]

Hello everyone!
It's that time of year. Just opened the pool, and I've already got questions!

I don't open the pool myself. My mom has it done by a professional who opens and closes it for us, and then I maintain it during the summer.
He's an odd guy, and not particularly talkative. Doesn't return calls, just shows up does his thing, and vanishes.
This year I noticed he had left one of the valves halfway closed, and I was wondering if he knew something I didn't or if it was just an absent minded thing, or perhaps a ritualistic offering to the pool gods?

We have two pipes running from the pool into the pump.
One comes from the two drains on the floor of the pool, the other comes from the skimmer.
When I got to the pool this year, the drain valve was fully open, the skimmer was left halfway open.

During the summer I just usually have all the valves wide open.
Because... well, I didn't see any reason not to.

Is this wrong?
Should I be leaving the skimmer only halfway open like he did? Does it even matter?

Thank for reading!

 

[ajw22]

Post pics of your pool equipment and valves.

 

[Jimrahbe]

FC,

I always recommend running with the main drain only open about 5 or 10% and have the skimmers open 100%

Thanks,

Jim R.

 

[FailedChemistry]

FC,

I always recommend running with the main drain only open about 5 or 10% and have the skimmers open 100%

Thanks,

Jim R.

Interesting. So the opposite approach.
May I ask why?

 

[Jimrahbe]

FC,

I want the skimmers to work as well as they can. The main drain does very little, if anything useful.

I have two rent house pools and neither one has a working main drain. And they work just fine.

Turn off your main drain for a week and see if you can even tell it is off...

My three choices in order of my preference would be..

1. Skimmers fully open and main drain just barely open.
2. Skimmers fully open and main drain fully open.
3. Skimmers not fully open and main drain fully open.

The world is not going to end no matter which you pick, I just like #1 best.

Thanks,

Jim R.

 

[TeanyV]

Hi FC,

The only thing I can think of is if there were lots of leaves/tree junk floating in the pool and the guy was trying to ensure the pump wouldn’t run dry if the skimmer basket got totally clogged. Maybe there were lots of leaves that sloshed off the cover when he opened it. Or it could just be a seasonal thing. Here in OH, trees are dropping all kind of stuff that floats, like seeds pods and pollen strings and those cottony fluffs. I like jimrahbe’s advice for option 1, but this time of year I keep the main drain totally open. Maybe he thought that closing the skimmer would help, although then all that stuff winds up on the bottom of the pool.

Or, maybe there wasn’t any reason and he just wasn’t paying attention.

~Teany