Should I ditch the canister?

Agreed,the nitrate problem you have is not due to your canister filter,but rather your lack of maintenance of it along with weak flow and no skimmer,perhaps even your water source and/or water change and feeding routine.Nitrates are fairly easy to keep in check,it just requires added effort on your part.I'd keep the canister and put your skimmer back on as well and step up your routine maintenance.

 

FIRST

Don't add the rock AND remove the canister at the same time, give some overlap so as not to change too many variables at once (AKA allow your GOOD canister bacteria you've built up to remove the potential BAD additions of even 'cured' liverock).

Second

Why not keep the canister filter? Good for circulation, quieter and 'cleaner looking' than a HOB filter...

Just remember to clean it when the output flow is noticeably low.


Eheim Ecco for 80 gallon + 65 pounds of Live Rock = my filtration for my 55g Reef.