I didn't mean to respond within the quotes...LOL
The Ecotech is 3100gph at $450. Pricey, true. It's typically used for closed loops and creating various waves if wanted...so for you application, you maybe paying for something not necessary.
Hey Knobhill,
If you end up going with the Deepwater Aquatics pump please keep us posted. Those performance specs are insane (almost to the point of being unbelievable), so I would be curious to hear if you think it's actually pushing that much more than your Rios.
For a pump to have a max head of 23.5' and push 3,700GPH @ 5.5' head on only 140 watts is crazy good.
Another option to consider:
Model / Output @ 5.5ft / Power consumption / Price/ Notes
Laguna Max-Flo 4280 / ~3,100GPH / 160 watts / $230 / Submersible, but some people run them externally
Mine has been running well for ~4 years. In my experience it is similar to the Reeflo Super Dart in regards to noise (both very quiet pumps) and much quieter than the Barracuda/Hammerhead. If you are sensitive to noise, I would steer clear of the Barracuda/Hammerhead (mine had an industrial motor hum to it).
If you want to stick with running two pumps, you'll actually get slightly better efficiency running two Max-Flo 2400s than a single 4280.
Model / Output @ 5.5ft / Power consumption / Price/ Notes
(2) Laguna Max-Flo 2400 / ~3,400GPH / 168 watts / $440
If my tank wasn't so tall, I would be running two 2400s.

I had a dart and just sold it! It was THE best pump I ever owned. It was on my old 480g with (2) 2" overflows and I had to tune it down. So I guess that is a good option.
Reeflo Dart/Snapper Gold/ 3200gph / 165w/ $360