what type of canister filter do you have?
When I was into freshwater aquariums, I used different canisters, a whole slew of models and sizes.
I commonly encountered leaks from lid sides and they mostly were caused by two things:
- Cracks on the lids or the canister body(water pressure or maintenance blunders, drops, etc)
- failed O-rings, they fail at some point - some faster than the rest
what I did,
- cracks, if very small cracks I fixed them with a light spread of silicone. Big cracks I once tried epoxy, but they rarely last.so bili na bago
- for O-rings, if the damage is not visible or can't be felt by the touch(look for cracks, breaks, etc) I apply petroleum Jelly all over the o-ring and they work good as new.note though, you have to add petroleum jelly everytime you clean/open the canister filter. if you can find a silicon lubricant, that works even better supposedly.
- but if the damage is severe on an o-ring, chances are you would have to find a replacement part. some china brands don't have spare parts. my eheim canister does so nakabili ako kay A1.
hope this helps!