Yeah, you can put a sump on anything. I think it really depends on what you want to do with the tank. If you want to run a 29 as a grow out for larger fish, then it’s probably beneficial to go with a sump. However, that same 29 being used as a planted shrimp tank is probably just fine with a canister or HOB. I do think that anything 125 or larger is better off with a sump, no matter what is in it.