Two holes in bottoms of both skimmer - should they be open or closed?

[JLFinATX]

Don't ask why, but I just noticed that there are two holes at the bottom of my skimmers. In the skimmer closest to the pool equipment (deep end) the hole closest to the pool has a cover on it to close it. In the skimmer at the opposite end of the pool (shallow), both holes are open (little cover is off to the side). Is this correct? Or did the cover shift in the shallow end skimmer and I need to put it over one of the holes?

Thanks for the replies!

 

[mknauss]

I know how mine work, but we might need a picture of yours.

Also, are your skimmers and main drain run back to the equipment pad with their own valves to control them independently?

 

[Cedarpool]

I have the same question. I have two skimmers and each one has two holes on the bottom and a cover that can be rotated to either partially or totally cover one of the holes. I have left them all open since that is how they were when I bought the house. Each skimmer and the main drain have their own independent valves at the pad.

 

[Bama Rambler]

In some applications the skimmers either connect to the main drain or to equalizers.
In main drain applications the 'cover' is used to adjust the flow between the skimmer and MD.

Since your main drain is ran back to the pad separately you may have equalizers on the skimmers. They'll usually be in the wall below the skimmer. In that case the 'cover' is used to close off the second port unless the level in the skimmer gets low and then it automatically opens the equalizer port to keep water going to the pump. If you don't have equalizers, then the extra hole is capped off and the 'covers' do nothing.