well, having beneficials is always better then not having them in any system. They are the most efficient method of turning nutrients into a conveniently absorbable method for the plants. They also stabilize the rez against all kinds of bad things that can happen.

Beneficials, in all my experience, do not cause a stinky res. I have run aero systems with 100 gallon res and only changed the res out once every 2 months. Just topped the res and did a little ppm adjustments. Water temp was even 76 Deg F. If the res ever smells bad I consider it a problem.

I never used H2O2 as i don't believe in killing the bacteria. But i had a lot of water movement and that may account for the healthy environment.