When I make it I use 1 carton of Goya Mango Nectar and TWO reapers. Let that simmer in a pot for 20-30 minutes. Let the mixer come to room temp and mix with your kombucha brew before moving to second fermentation. It'll give a noticeable burn, but the mango counters it nicely. Don't be tough with the peppers, those TWO go a long way. My first attempt I did six because I had no gauge and it felt like I was drinking sandpaper.

When reapers are out of season, you can substitute with 6 habaneros. Same level of heat (maybe a bit less), but slightly different flavors since reapers and habaneros' fruity flavors are different.