Aeration Methods: Pouring vs. Fish Tank Pump vs. O2

Greetings fellow homebrewers!

I'd like some feedback on my current aeration technique. I built a fish tank aeration system but had no luck with it on my last brewday. I need a stronger pump. So I used my old technique. It goes like this:

1. Cool wort in the kettle with my immersion chiller
2. Pour the cooled wort back and forth between the kettle and a sanitized bucket.
3. Pour my yeast starter into the bucket with the wort.
4. Pour back and forth one more time.
5. Pour into carboy.

I always end up with tons of foam and lots of oxygen. My fermentations are typically very vigorous and fairly fast (4-5 days)

I know a lot of you use aeration and oxygenation systems. What are the benefits to using these systems over pouring back and forth? John Palmer illustrates this issue in "How to Brew" but doesn't mention it in the Aeration episode of "Brew Strong."
Is it a cleanliness issue? Am I running the risk of contamination by using ambient air? I do it outside in clean, fresh air. I have to assume the yeast will take care of any baddies.

I'm interested in what your thoughts are on this topic. Thanks a lot!

NATE

i like using a fish tank aerator. but i have used your pour back and forth method as well. both seem to work equally well. what went wrong with your fish take aerator?

Well, I hooked the fish take aerator up and put the aeration stone to the bottom of the carboy. I couldn't see ANY bubble coming out of the stone so I made the assumption that the pump is just too weak. It's a very old pump that I had sitting around so I think I need to invest in something stronger. I am just wondering about contamination from outdoor air. What are your thoughts on wild yeast and other bacteria in ambient air?

if you do decide to go the fish tank aerator get an inline air filter for the air out line. it will filter out any wild yeast or bacteria you need to worry about.

as far as the sloshing back and forth method. yes there is still a problem with wild baddies but cant imagine it would be any worse than using an aerator with a filter on it. you, me, and lots of other people do that. if it was risky i don't think it would be as popular of a method and people would be screaming at the noobs to not do that.

There was a recent thread with a link to a study on this. Basically, unless you are going to inject O2, there is no difference between air injection and shaking. Injecting with O2 does put more O2 in the wort, but it might not really be noticeable in the end product (i.e. there is a minimum needed and shaking can easily get to it).