Knowing that this was not a "normal" spider web, I decided to take a second look. When opening the access door my eyes caught a black critter running down the side of the tank. Pulling the tank out of the base I came across this beauty.
Why it's a mature female Latrodectus hesperus*, better known as a Western black widow spider guarding her small clutch of eggs. I was able to snap a few shots of her while also acting like a 10 year old boy and poking near her with a stick. She didn't budge. With the black widow being the most venomous spider in the US, sadly I had to exterminate the little girl and remove the egg sac.
*Latin name listed for the benefit of Canoelover.