The original 32 mm grommet has too small hole and adapter to 38 mm hose with nuts that was for filtration was making it even smaller.

Decided to make my own grommet.

Inner bigger thread is for vacuum hose or other standard compartment.

Printed from PET, cut the old grommets out and used the hole for these. Used silicone for gluing on both sides.

And it worked several years in my salt water in summer and winter.

For winter there is the inner cup. Standard cup from outside. It was closed from both sides then.

(This year sold the pool with these grommets, I am in-ground pool. But want to share this helping feature.)

Use some good material, not PLA :)