I do not have DO meter so I do not know what my O2 levels are.
I aerate with similar method in the transfer to the fermentor.
I have about 4 ft 3/8 clear tubing with pinhole on the BK end.
Pinhole allows air to be sucked to the tubing that mixes with passing by wort in the transfer.
On fermenter end I have a wort Sprayer like this:
![](http://www.northernbrewer.com/media/catalog/product/cache/1/image/265x/5e06319eda06f020e43594a9c230972d/i/m/image_617.jpg)
I have fermented 1066 beers with no problem.
What I mean with "no problem" is 2 week fermentation and about 1014-1016 FG.