Maybe you already know this?
Once siphoning begins, it is not neseccary to keep the tap water running (depending on how much lower the sink is than the tank).
Pythons have been around for at least 4 decades, I started using them in the 80s.
I believe they were originally invented to drain and fill water beds (popular in the late 60s and throughout the 70s.
I stopped using them when I realized I could use the gravity flow from my sumps to reroute tank water to my garden, by opening a valve, it would send hundreds gallons of old water from 5 tanks per sump, all at once outside. (I usually had 3 sumps all plumbed to the2" line heading outside to Semi-permanent plumbing in summer, old water went from the sumps in the fish room straight to the veggies.
It really saved at lot of time, with 20 tanks, over 1500 gallons, and used water twice.

Just by opening the red valve above, old tank water was automatically sent outside.
Old water could also be sent to rain barrels, and ponds.
