Thanks to everyone for the replies so far!
I'm going to continue posting here until my sump is operational, so please bear with me!!! Don't worry, I am an avid internetter and am not relying solely on you good people for
all of my answers.
One little bit of wisdom I've picked up working in construction is that
if something looks stupid: it is stupid. It doesn't take a plumber to know that I did it wrong haahaw D'OH!. My whole life is one mistake after another so why should I complain if my aquarium follows the same pattern?
C'est la vie. The worst part about DUMPING money into an aquarium is that half the time it's the wrong decision! AHH
the other bad part about dumping money into an aquarium is that our coins are made of copper.
OK down to business:
So far most of the advice I've received highlights the following issues in my setup:
1. I teed two drains down into one and cut the radius down by 50%. This will increase the output pressure of the drain (fourfold) but drastically reduces the flow rate. Most of the recommendations I've received suggest that I keep the box operating as TWO drains. Run one to the skimmer and one to the sump.
2. It's way more complicated than it needs to be.
I've come up with two solutions of my own and so
my NEXT question to post in this thread is as follows: WHICH SOLUTION IS BEST FOR MY SETUP?
Solution 1: Keep one of the drains in my overflow box as an emergency, or ancillary drain, which only kicks in after the first one fails or backs up. This is easily accomplished by cutting one of the PVC standpipes or installing a larger one on one side. The e-drain will go directly to the sump while the main drain will go directly to the skimmer.
This way I am only using one drain 99% of the time. I think this will be OK because it is 1" PVC and it should drain at near-capacity if I'm pumping 300gph into the tank.
Solution 2: Remove (and sell) the $125 overflow box
that is rated to drain over 1000gph. It vastly exceeds the pump, and the skimmer, and will NEVER operate at capacity on this tank. It will gurgle 24/7 for as long as I insist on using it. It relies on two U-tube siphons. Construct a basic PVC overflow which pipes to the skimmer, and tees to the sump (although I am still skeptical about this it seems like the right thing to do).
Last thing: if door #2 is the winner ... is there a type of valve I can install that will direct all flow to the skimmer until there is an emergency situation, at which time it will re-direct the flow into the sump?