my light fixture was close enough that the cord got a little wet and lights started zapping and crackling
Yikes! Not good in any scenario.
When testing new equipment, I try to first plug it into its own powerstrip that has an on/off switch. And I set it at a place where I can reach it immediately.
This saves me from having to dive into the under-tank cabinet and unplug the cables.
With HOB skimmers in particular, I test it first outside hanging from a plastic bin and run it for a few minutes to make sure that I locked the fittings in properly and there are no leaks.
Your skimmer looks like it was modeled after the Reef Octopus. But your return pipe looks smaller compared to the Reef Octopus design.
This could mean that if the water intake volume is high enough, it could overwhelm the return pipe and the return chamber could overflow.
In your case, not having the air intake hooked up meant that the pump was pumping 100% water and that could have exceeded the return pipe's capacity.
The return pipe only has gravity on its side. The intake uses a pump designed to defy gravity :)
Even the Reef Octopus (BH1000 and BH100) can overflow at the return chamber if the air intake is clogged.
What would be a nice enhancement to these products is somehow have an overflow channel on top of the return chamber so that any overflow will flow back into the aquarium instead of the floor.
I googled the skimmer model that you have and it looks like in terms of price it is just a tad under the price for a Reef Octopus BH1000.
Also, with this type of skimmer design you do not get to control the amount of air intake. They are designed to operate with the airline 100% open.
The way you tune the skimmer is by raising or lowering the collection cup so that the skimmate is at the consistency that you want.
The rubber band is what you would use to hold the collection cup in place.
The Reef Octopus also has a screw on one side to help lock the collection cup in place. I could not tell if your skimmer has that same lock screw.
