+1 on Vircomore's post
I can't use my kitchen sink because there are no threads on it whatsoever. It has that hose shower thing. So I use my bathroom sink. You need to take off the aerator/filter attachment to expose the threads. Some faucet has outside threads and some has inside threads and both will be accomodated by the python.
Your sink should also be deep enough that you can fit the attachment. My sink can fit the attachment but when draining I have to watch the water going down the sink because its not deep enough that if the water is flowing too fast, it can overflow.
Here is what I do when I PWC
1. Attach Python to the faucet.
2. Put the syphon end in the aquarium (make sure the switch is to drain and that the syphone is closed [there is a switch to turn suction on/off]). This is also the time I turn everything (heater, filter, etc.) off.
3. Turn water on water all the way.
4. Switch suction to on and start vacuuming gravel. Drain water (I do 50%).
5. Turn suction switch off and faucet water off.
6. Put in dechlorinator for the whole tank volume (e.g. mines is 29 gallon so I put enough dechlorinator for a 29 gallon)
7. Turn faucet water on and adjust water temp to temp of aquarium water (I use my hand to tell).
8. Twist the python attachment to FILL.
9. Turn suction (in this case opening for filling of water) on. And fill it up.
10. Once filled up, I turn faucet water off, detach the python and put it away.
11. Turn everything back on and make sure your filter is not running dry.