Exterior overflow mounting options

[Scubasteve11]

I purchased a used tank that came with preexisting holes drilled. Trying to make the best out of it.

Does anyone see any concern with mounting the exterior of this overflow box without a bulkhead for support? It will only be attached with silicon. The predrilled hole is huge and won't fit any of the overflow boxes out there.

 

[Crabs McJones]

I don't see an issue with it. All it is is a hole from inside to outside. A bulkhead is simply a hole from inside to outside A bulkhead would be used if it was going from inside to outside where it can't get wet such as external plumbing ect... but if it's going from inside the tank to the outside glass box, just leave it

 

[Scubasteve11]

Thanks @Crabs McJones