Auto shut off skimmer collector questions?????

[Canadian Man]

So there is a 1/4" or so output on the bottom of the collector cup.
There are 3 smaller holes in the lid of the skimmer and the cap just snaps on and off. So the cap is kinda a tight fit but not completley.

For this to work I would have to plug the holes, which is easy but how the heck can I get the cap to be sealed.???
HMMM I suppose I could make a flange for a cap???