UGF to feed a closed loop?

[83years]

A closed loop seems like a rather good idea to me (I have zero reef experience btw) but I would think the chances of a fish or invert getting sucked up is pretty high. To get past this could an under gravel filter be repurposed to stop anything getting into the pump? Just so there's no confusion, the UGF would not be intended to be used as a biological filter, there's a sump skimmer and refeguim for that.

The set up I am thinking of is a set of inlet pipes below egg crate covered in a mesh, topped with course sand. The outlet from the closed loop would be at the water surface.

Is this crazy or does it have merit?

 

[lapin]

As long as you have a strainer, a closed loop will prob not suck anything up unless its a sick dying fish. I had a closed loop on a 125g with a dart/snapper hybrid pump . My cleaner shrimp would clean the strainer. I used this strainer.
https://shop.dursostandpipes.com/collections/strainers

 

[ca1ore]

Yup, have had closed loops on my tanks for years. Use a strainer! Hasn’t sucked in a fish yet.