Just measured my 2217 at work. 15" to the canister top (you're good there). 19-20" including the outflow tube. Now if you can angle the flexible tubes towards the back of the tank (space between wall and tank), I'm sure you'll be fine with this clearance issue.
Cool! Thanks. I currently have a Japanese canister on my 55gal and it seems to work pretty good. But man the maintenance on it is a pain and the directions are all in japanese. Which makes things way harder than they should be.
That's not a 125 - that's a 210. A 125 is 72x18x24. Two totally different animals in regards to filtration
If you are buying a tank that is 210 gallons - go with a wet/dry and large canister filters (eheim 2260/2262 or fx5). I use this set-up on my 180 (72x24x24)and my maintenance is so easy - just rinse out the pre-filter on the wet/dry when doing a water change and rinse the media (with tank water) on the 2262 every 3 months or so.