When I went to the local university's aquaponics research station last fall, they told me the most expensive part of your system will be oxygen. They saw TREMENDOUS increase in yields when they started adding O2 as opposed to just aeration, so I've spent some time in the last few months trying to get an oxygen concentrator for less than a few hundred dollars.

Guess what?!
I got this and another for FREE! They were kicking around at a local hospice for years, never being touched. They were happy for me to just make them away.

I added a little reactor to help dissolve the O2 before goin to the GBs


It's been a couple days but it looks to be having a benefit in my herb garden. I plumbed the supply line so that it adds the oxygen-rich water to the bottom of the GB, as I am hoping to prevent as much O2 from gassing off as possible. Since I'm adding O2 directly, and not bubbling in atmospheric air, I want as little splashing and turbulence to and in the GB as possible.
I'm still letting it splash when the GBs drain into the pond Bc O2 concentrations over 20ppm are lethal to fish.