It may come as a surprise to learn that darksuckers also operate on a celestial scale; witness the Sun. Our Sun makes use of dense dark, sucking it in from all the planets and intervening dark space. Naturally, the Sun is better able to suck dark from the planets which are situated closer to it, thus explaining why those planets appear brighter than do those which are far distant from the Sun.
Occasionally, the Sun actually oversucks; under those conditions, dark spots appear on the surface of the Sun. Scientists have long studied these 'sunspots' and are only recently beginning to realize that the dark spots represent leaks of high pressure dark because the Sun has oversucked dark to such an extent that some dark actually leaks back into space. This leakage of high pressure dark frequently causes problems with radio communications here on Earth due to collisions between the dark particles as they stream out into space at high velocity via the black 'holes' in the surface of the Sun.
As with all manmade devices, darksuckers have a finite lifetime caused by the fact that they are not 100% efficient at transmitting collected dark back to the power company via the wires from your home, causing dark to build up slowly within the device. Once they are full of accumulated dark, they can no longer suck. This condition can be observed by looking for the black spot on a full darksucker when it has reached maximum capacity of untransmitted dark... you have surely noticed that dark completely surrounds a full darksucker because it no longer has the capacity to suck any dark at all.
http://www.zerobeat.net/drakelist/darktheory.html