I used three canisters (eheimx2, FX5) on a 170G for years. I always dreaded cleaning it out, worried about breaking the connectors, and pouring out 2" of nasty brown thick gunk from the bottom was gross. Cleaned every 4-6 months, one at a time. I really wanted a open filtration system and wanted to incorporate filter socks and plenty of assessable biomedia. Too much bypass and worried about clogging of biomedia with all the gunk in a canister.
So I put together a sump, and packed all the canisters away. My filter socks are replaced 2-3 days, my ugly heater is housed there, and sump is super clean. IMO, a Wet/Dry or any type of sump is preferable to canisters, if it is feasible within your system.
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