Transitioning from hob to canister?

I would either leave it running for a couple of weeks or else just take all the media from the HOB and stuff it in the canister. That is what I did and it worked great. Of course now I have added the HOB back on the tank for extra filtering which I love. A Flluval 304 and an Aquaclear 30 on a 29 gallon tank. The fish love it.
 
Agreed with TKOS method or just give it at least 3 weeks to be sure that the new media in the canisters has been seeded with the beneficial bacteria.
 
Oh, one more question.

What about air to the tank? I know the hobs provide good air via the waterfall effect.
How do the canisters provide air to the water?
What adjustments if any do I have to make?
 
Any ripples on the surface will create plenty of air exchange. If you find your fish are gasping at the surface then you might need to increase the agitation. This can be done by titling the outtake upwards so that it moves the surface water more. In my tank (29 gallon) I recently readded an HOB (it has a Fluval canister) as the summer heat has obviously affected my white clouds. Adding the HOB has done wonders and I figure I will continue to keep both filters. Plus it is much easier to add things like filter floss to the HOB for quick water polishing.
 
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