2 Skimmers, unclear labeling


New member
Apr 12, 2019
San Diego
Hi everyone. Joe from San Diego. I’ve been studying on how my pool equipment works (just bought house with a pool) and it’s a kidney shaped pool with 2 skimmers.
So based on what I read I’m assuming 1 skimmer has the two ports connecting to the main drain and the 2nd skimmer probably just sucks. Where I’m getting lost is the valves.

The suction line from the pump goes to a splitter which connects three things:
1) vacuum line - this has its own valve to shut it completely off
2) a second split with the following labels:
a) Skimmer 1 / Main drain
b) Skimmer 2
There is also a valve, but it’s locked between 10 o’clock and 2 o’clock, meaning you can’t completely put it towards either side.
3) an electrically operated valve that goes to an unlabeled pipe. This has something to do with spa because it only activates when I turn on the spa - I’m 90% sure it’s isolating the suction and directing only at spa

I have no idea which skimmer is 1 versus 2 but am assuming the farther away one is 2. The home has lots of problems as it was built on the cheap.

Neither skimmer ever seems to have any flow of water towards them. Based on all the videos and things I’ve read, my understanding is at the valves I should be able to chose between main drain and skimmmer. I’ve never read about a combined pipe skimmer/main drain with no option to select one or the other.

I’ve read in detail how to attempt to clear obstructions but I can’t do this because I can’t figure out how to get suction to the skimmers at all.

Would really appreciate any help

Edit: I should add the suction works fine, ie vacuum operates normally as does filter and heater
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TFP Expert
LifeTime Supporter
Jan 6, 2010
San Dimas, CA (LA County)
Welcome! :wave:

Let's address things one at a time. Skimmer1/drain should have two holes in the bottom and a device that looks like a flying saucer between the basket and the holes. Or some kind of lever to flip flow from skimmer to drain. If the saucer type, this is how it works.

As for no flow, you must be getting some, or there would be no circulation. I'm going to make a wild guess and ask if the weirs (flappers) are in place at the skimmer throat. If they're not, you won't see much action in the skimmer and they won't work as a skimmer. They'll just be a water intake.


Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
Bedford, TX

In your pic you have the vacuum port wide open.. If this is how you leave it, it will take a lot of suction away from the skimmers..

I suspect that the flying saucer in your Skimmer/Main drain is not there... If this is true then you functionally have no main drain which is no real loss as you don't really need one.

I second Richard's Weir door ideas... And the key to skimmers is do you have trash in your skimmer baskets, not how much the water moves. I run my pump pretty slow and there is almost no "action" on the surface, but my skimmers work just fine.

I might be wrong, but it appears you have an IntelliFlo VS pump... so that leads to the question.. "At what speed are you running the pump(s) do you run the pump, and at those speed(s) what is the filter pressure?

Looks like you have a fairly large cartridge filter.. When was the last time it was cleaned?


Jim R.


Well-known member
Apr 6, 2016
San Diego, CA
I’ve never read about a combined pipe skimmer/main drain with no option to select one or the other.
Not sure how helpful this is, but while it's not common it is possible. Ask me how I know 😑... My skimmer and main drain are tied together underground somewhere. There is only 1 hole in the bottom of my skimmer and no valves anywhere to adjust the suction between the two.


New member
Apr 12, 2019
San Diego
Ok - first of all thank you everyone so much for replying! Seriously this is a fantastic resource. Here’s what I did after reading everyone’s posts:

1) removed the baskets in both skimmers. Identified both had UFOs. Under both UFOs were two openings.

2) the weir doors were installed upside down so flipped them around. Incremental improvement. When holding door closed on 1 skimmer water began draining out of the skimmer. On the other skimmer no change when doing this. Removed UFOs from both and noted that 1 skimmer had no perceivable water flow with UFO in place, but water flowed quickly with UFO removed. Will replace defective UFO. Skimmer 2 UFO operated normally.

3) turned off vacuum line. 2nd skimmer now operating a little bit

4) removed stops from valve that selects between Skimmer 1-Main Drain / Skimmer 2. Now that I could completely turn off a skimmer or the other was able to identify which is skimmer 1 and skimmer 2. Turned valve again so that it was midway between pipe 1 and 2. Now suction preference given to skimmer 1. Turned valve again to give preference to skimmer 2. Now have even suction between both.

Just need to replace the one defective UFO. The thick layer of bugs on the top of my pool is now disappearing (they were too small for hand skimmer)

Will get an electronic valve to turn vacuum line on and off automatically when pool is in “clean mode” so pool floor isn’t ignored.

Thanks guys!
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