cynar

It was first found in monkeys, but actually originated in rodents. It should technically be rodentpox.

Also, racists and homophobes used it to create stigma against gay men. In was/is particularly prevalent in that group. There were rumours that you caught it from sex with monkeys.

Basically it was renamed to pull the teeth of a nasty and insulting use, and to break a misunderstanding on its source.

It depends on the hose and the flow rate. They can vary a lot.

Also, your not just clearing the stagnant water, but also anything that was growing in it.