After 12 years, the pump in our fosse filter bed has failed. Having hauled it out, I discover that it was a 30€ Brico Depot pompe vide-cave, 250W rated at 8000L/hour.
Searching for a new one, prices seem to range from 30€ to 750+€.
Given that there old one worked well for 12 years, are there any good reasons to spend more than the minimum?
I wouldn’t think so. Is there some MTBF (mean time between failure) rating. If it’s a big hassle to haul out maybe a slightly greater investment might be warranted to avoid having to do it again. Lidl do a couple of good pumps, don’t know if they’d be suitable. I’ve one that has been through the wars and still works fine, even after me having to chip the dried cement off it 
Be sure that it’s the pump that’s failed, and not the float. We had a fosse in Deux Sèvres and the pump seemingly failed, but a quick electrical test showed it was the float switch, which was only five years old as was the pump. I was quoted a large ammount for an exact replacement but bought a cheap alternative from a local brico very cheaply, similar to this
It was still working 8 years later and never needed any adjustment or furtling with like the older ball type that failed did.
Thank you both. The pump had definitely failed. It looks as if a bearing failed, the windings overheated and blew leaving the device open circuit.
I now remember that a few months ago the fosse circuit on the tableau tripped. Having reset it, it didn’t trip again but stupidly I failed to check the actual pump. Lesson learned…
Luckily it’s very easy to get to and replace - the original installer did a good job.
I don’t think I’ll go as low as 30€ but look for something around 100€ with bearings made from brass rather than nylon.