Okay, to clarify, when you do your water changes you probably drain the old tank water into a bucket or container, right? I meant to rinse the filter cartridge in aquarium water after it is removed from the aquarium.
Secondly, your Penguin 330 does not have the white biological cartridges, nor does it need it. The biological filtration is performed by the bio-wheel and it is much more efficient. The Regents don't have the bio-wheel, instead they have those white cartridges. I forget what they call them but it is a place where the beneficial bacteria colonize. Since you never remove this cartridge eventually it will fill up with large amounts (or so the thinking goes) of beneficial bacteria to get rid of the ammonia and nitrites.
They're definitely not the best at biofiltration but try only replacing one cartridge at a time and also try rinsing and reusing the cartridges as long as possible. If you still have ammonia spikes you may want to get a Penguin or Emperor with the bio-wheels. My guess is as long as the filter is big enough for your tank and you're not over stocked and you perform routine weekly or bi-weekly water changes of 15%-25% you won't have any more problems.