BTW you should run those time-to-drain numbers again. The outlet looks like its about 2cm in diameter. The sound seems to be mostly water impacting on the side of the pail.
Tank height 25
Radius 0.20Time 1 Bar 44.94 minTime 2 Bar 3.52 min
Radius 0.30Time 1 Bar 19.97 minTime 2 Bar 1.56 min
Radius 0.40Time 1 Bar 11.23 minTime 2 Bar 0.88 min
Radius 0.50Time 1 Bar 7.19 minTime 2 Bar 0.56 min
Radius 0.60Time 1 Bar 4.99 minTime 2 Bar 0.39 min
Radius 0.70Time 1 Bar 3.67 minTime 2 Bar 0.29 min
Radius 0.80Time 1 Bar 2.81 minTime 2 Bar 0.22 min
Radius 0.90Time 1 Bar 2.22 minTime 2 Bar 0.17 min
Radius 1.00Time 1 Bar 1.80 minTime 2 Bar 0.14 min
2cm diam is MUCH too quick.
