Steamy Stacks is where you need to be in this latest Fortnite challenge. It's not a tough one to complete, so you should be able to get it done fairly quickly.
Where is the Purple Pool located?
The Purple Pool is found north of the Steamy Stacks point of interest; in the heart of the main building, whose tinted windows are colored purple. You shouldn't have too much trouble finding it right after you land.
For the challenge to be validated you just need to perform a few strokes. It's not yet clear what exactly the purple liquid is, but it could have something to do with the end of season event.
This challenge is undoubtedly one of the easiest of the batch this week, since the only difficulty here is not getting killed. While many may hotdrop at the start of a match, it should be relatively free later in games given its location in the extreme northeast of the map. If in doubt, play in Team Rumble mode, where respawns are infinite.