I have been through numerous Juwel filter heads in the 14 years of owning a Juwel Vision 180 tank.
- Yes, they do sometimes just stop working, no reason at all. If you have a multimeter (and understand Ohms) you will find the pump head is open circuit implying the motor windings have gone open circuit, which is annoying considering the windings are embedded in resin and should last for ever.
- If the fuse has blown, get worried as that implies a major'ish fault, though sometimes fuses do fail for no reason at all.
- When the Juwel impellor shafts were stainless steel, as opposed to newer ceramic shafts, they used to wear away and the pump head starts making a lot of noise.
- I have had an impellor magnet crack, in which case it didn't turn, but just buzzed. New impellor fixed that.
- I changed the 600l/hr pump head to a 1000l/hr pump head but suffered from the sponges collapsing and blocking which then lead to the impellor shaft wearing. Stick with 600l/hr.
Unfortunately, like most fish tank filter pumps, there is little to repair if it stops, so best option is complete replacement at about £30 (Ebay).