Assuming the bulk of the nitrifying/denitrifying bacteria in your system colonized on some form of media in your canister filter, a good part of the biological filter in your system was just removed.
With sufficient live rock, etc. in your system, it should even out again in the long run. In the mean time, what you do depends on what is living in your system. If nothing is alive, don't worry, leave it alone and your mini-cycle will complete fairly quickly. (I target as high as 3-4ppm in a new system.) If you have livestock, consider water changes or a product like Amquel or Prime.
Keep an eye on livestock over the next couple weeks. You're probably fine, but if anything dies, you want to remove it quickly to avoid any kind of chain reaction. That's pretty much the textbook definition of "tank crash."
In the future, consider moving some of the biological filtration media to the new sump to avoid nuking your biological filter. Remove it slowly over the course of a month or two to avoid this kind of mini-cycle.