Too much suction in one skimmer

[Throwaway543]

My pump pulls from two skimmers and a main drain. The two skimmers run to a tee near the pump and then connect with the main drain pipe in a 3 way valve. Everything is 1.5" plumbing.

My problem is that the closer of the skimmers pulls much more water than the other rendering the 2nd one pretty useless.

I am redoing the plumbing near the pump this spring and am thinking of setting up valves on the the skimmer lines in front of the 3 way valve so that I can regulate how much water is getting pulled from each skimmer. Any reason this won't work, shouldn't be done, or way it could be done better? Thanks.

[Teapot]

This situation is quite normal, some skimmers have a little movable plate in the bottom under the basket to allow adjustment of the flows, is that in yours?
If not then the addition of valves is your next step.

[Throwaway543]

I do have a piece that goes at the bottom of the skimmer. It has the little plate to restrict flow, but it also has the device that seals up the inlet if no water is in the skimmer. My issue with that was that when my variable speed pump primes, it sucks the thing closed even when there is water in the filter and when the pump slows down it doesn't always open back up.

I guess I should just bite the bullet. Any advantages or disadvantages to going 3x 2-way diverter values (Skimmer 1, Skimmer 2, Main Drain). Instead of 2x 2-ways on each of the simmer lines, connecting them with a tee and then sending that water to a 3-way that combines the main drain?

[Teapot]

Hmm, most flow restrictors are flat plates that are screwed to the bottom of the skimmer. Have you a picture of yours?
Water takes the path of least restriction so any reduction in the skimmer lines will mean more flow through the main drain so I recommend 3 valves.
That said main drains do very little to aid the pool water. Dirt enters the pool from the top so is best skimmed out. Dirt that hits the bottom of the pool stays there unless pushed into the main drain.