That’s good to know. How long in terms of time would one have to purchase a new filter? Basically, how long will the fish live for without a running filter?
Replace within 24 hours, 48 absolute max, perform large water changes in the interim, put all old media in new filter and test water for ammonia & nitrite every 12 hours in case you get a mini cycle. the longer you leave the bacteria without food and oxygen the more of them will die, so definitely replace ASAP, but there is a grace period of a few hours where you're ok (like if you have a power cut, forget to turn back on after cleaning etc)
how long depends on stocking level, but you deal with it by doing large water changes like a fish in cycle.
Might sound silly but I like to be prepared incase something like that did happen. I’m surprised how little time one has to get a replacement, I don’t think anyone stocks the filter I have locally so will be very concerned if this does happen.
Is it known for filters to just pack up at all? All does it not really happen?
It happens yes, how often nobody could really tell you. Always pays to have a spare around. i keep the 305 filter that came with my tank in the garage in case i need spares for the new one. if the one in my 90litre packed up, i can get one for £20 locally pretty quick.
theres not many moving parts in a filter, and not many seperate components either. for my eheim external, a couple of ceramic shafts and a spare motor/lid i think would get me sorted quickly. both quick fixes.