My filter won't prime

[DangerousMouse]

I cleaned my Fluval filter out at the weekend, now I can't get it to prime - does anyone have any tricks? The canister is full and I've been trying to prime for hours.. Sore hands! I've currently got an internal filter going as emergency back up, but its not big enough for long term.

Id a fluval 305 & as long as it was full (like yours) when you primed it it drew water through it & sprayed out the outlet with each pump. Though if doing it when empty it just took ages to fill the canister but still worked. Is any water going through? If there was a leak or it wasn't sealed it would be obvious from the spillage. You could try disconnecting the pipes & check the tap valve isn't jammed?