Blow out yer dead

Did I mention our polytunnel? I did 
For nearly 20 years, it has been central to our lives: drying laundry; growing beans, tomatoes, spinach; sawing, stacking and storing firewood; saving pot-plants from frost; eating lunch; entertaining children. No more than myself, the tunnel is a bit leaky in its old age, but is still much drier than outside.

And therein lies a problem: it never rains in the tunnel, so every drop of water has to be brought inside. I do as much of this hydraulic movement as possible by gravity or by siphon and the tunnel-faucet is the source of last resort. Usually [cw: Ireland!] the rain falls on the regular and when there is a ppt-pause we have 2½ tonnes of storage capacity to keep the plants alive. This winter, I've been working to bring water into the tunnel even if nothing much is growing - I think I'm storing most of the surplus deep in the soil - there being resistant to evaporation.

Crates and herring barrels, buckets and watering cans and Lots of 20mm pipe make up the infra-structure, which among other things stops the laundry getting covered by dust-storms. The Beloved emerged from hibernation in mid-Feb to put manners on veg-beds in anticipation of Spring sowing. She complained about A Smell emanating from either the once-pink storage crate or the watering cans. Mortified I was and went up to give the crate its annual scrub: (rain-water + sunlight = algal sludge). I then took the empty crate down to the nearest water supply - the 120lt herring barrels [in the middle distance R] - for a rinse. I filled the green watering can from one barrel and started to pour . . . but it blocked up after a few seconds. Sooo, as y'do, I put the spout to my lips and >!ptui!<. That was but a temporary fix and after three [3x] blow-back attempts I gave up on the watering can and sluiced out the crate with a bucket.

I then turned the watering can upside-down over the now empty bucket 
Q. to forensically investigate [cw: scientist!] what was causing the obstruction. 
A. A dead mouse, when long steeped in water, is soft enough && tough enough to exactly stopper the spout of a standard watering-can. I've been sucking and blowing on hoses and pipes [cw: siphon] all my life and have been 'surprised' often -- but killed = never.