need help draining water from very large pond filter

i'm sorting soem guys pond out or him as he doesn't have a clue
its a big 10k litre to 15k litre
i'm not sure hwat the filter is caleld so i have included photos of the
filter and all pipes

[image: http://i2.photobucket.com/albums/y49.../IMAG0048.jpg]
[image: http://i2.photobucket.com/albums/y49.../IMAG0049.jpg]
[image: http://i2.photobucket.com/albums/y49.../IMAG0050.jpg]
[image: http://i2.photobucket.com/albums/y49.../IMAG0051.jpg]
[image: http://i2.photobucket.com/albums/y49.../IMAG0052.jpg]
[image: http://i2.photobucket.com/albums/y49.../IMAG0053.jpg]

can anyone help me by telling me how to work this filter?
i need to empty all the water out of it as it has been left turned off
for a long time and its very dirty and smelly
does anyone know how to do that?




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roboticnat