Ernie,
It's not at all uncommon to have return pipes low in the tank, as your does. My return goes down about halfway in my 80g. When I built the return, I drilled 2) 1/8" holes just below the waterline. I then drilled 1 hole just above the water line but at a 45degree angled towards the water. In 2 years it's never clogged, the other 2 have. Because the angled hole is so close to the water, it's silent.
Since my tank was never drilled for an overflow, my original cpr back box used to scare me on a regular basis, that and keeping the thing clean. I finally decided on the Lifereef box and sleep much better. I also installed a cutoff switch in my sump should the water level drop suddenly, assuming the back box had failed and the tank was flooding.
Regards, Eric