Sealing simmer cover

[Diver]

I have an inground pool with a Hayward SP1085 wide-mouth skimmer:

The square cover simply sits on top and has 2 holes for screws:

The skimmer also has two holes for those screws to go into, implying that the cover can be secured. Under cover there is a square groove that looks like it would accept a gasket and when tighten with screws it could be potentially water tight.

The skimmer cover is close to the end of the pool winter cover and it allows for skimmer to be filled with water when pool is winterized. With the pipes sealed and with some antifreeze and something compressible in the skimmer there is no danger to the skimmer, but in spring before pool is open, the water in the skimmer gets pretty nasty.

I was wondering if the skimmer can indeed be sealed like that? I can't find a gasket that would go under the cover and with only two screws I doubt it will create a water tight seal.

Anyone had any experience sealing it like that?

 

[JVTrain]

If you want to keep water from leaking through the skimmer lid and actually see it as a problem, I would lay a bead of plumbers putty all the way around the outside of the lid, under the screw heads on each side and put a proper sized rubber stopper in the center hole.

 

[Hayward Pool]

The two screws are there to secure the lid making it harder to be left off and become a hazard. There is no gasket to seal the lid.