I'm doing a leak test and have a quick Q

[Redrover]

I see that it's plumbed to the skimmer...no return that I can see
What type of skimmer...looks like a H/S..If it was mine I'd have it in the sump, I don't think you have the room

[Redrover]

I was at Hidden Reef today and talking to Marc in regards to your problem.
He has sent you a PM to get in touch with him before you go any farther as you may have water everywhere. I would also have as a sugestion have someone do your plumbing,this will give you piece of mind that things are done right.