Wort Transfer Pump Question

I just bought a cold wort transfer pump from Williams Brewing:

http://www.williamsbrewing.com/SELF_PRIMING_PUMP_WITH_VARIABL_P1940C182.cfm

Using it for the first time today, I noticed that there seemed to be a lot of bubbles being whipped up during the transfer to my keg. This obviously caused a good amount of concern on my part. A couple of questions:

First, does anyone else have this pump (or a similar one)? Do you see the same thing when you transfer fermented wort?

Second, are these bubbles air or are they CO2 coming out of solution during the transfer?

Third, if they are air bubbles (this pump does seem to move a lot of air along with the transfer as the filter housing never really empties out the air bubble during operation), would this be a problem in the keg? A little more info regarding this - I do not secondary, but rather transfer to a keg and allow to condition for another week or so at fermentation temps. Would this action clean up any additional oxygen that the transfer created?

So many questions...

...your experience would be helpful. Thanks ahead!

My guess would be that it's a combination of the dissolved CO2 coming out of solution in the fermented wort and air that was in the filter housing. Did you somehow purge the filter housing of air before you began the transfer? I think that's what you are supposed to to in order to avoid exposing the wort to oxygen in the air. One technique is to flood the filter housing with a no rinse sanitizer (StarSan for example), then begin pumping. Wait until you have displaced all of the Sanitizer and have only beer discharging before you begin filling the keg. I have never actually done this, but that's what I read somewhere on how to do it. I don't know of many who pump from a fermenter through a filter into a keg. Most keg the beer directly out of the fermenter then use CO2 to push the beer through a filter to a second keg.

I have wondered about the SS strainer in the pump. Is that possibly adding to the bubble issues you have? All in all I have been very happy with the CO2 push that I never saw the need for a pump on the finished beer side of things.

+ what Catt22 says.

I'm thinking that so long as there are no leaks in the fittings anywhere then any air or whatever must already be in the system. The air has to come from somewhere if it's not already inside. OTOH, if it's only CO2 and not air, there's really nothing to be concerned about. I would worry about the air in the filter housing though, if were not filled with something prior to starting the pump.