Descaling Breville Espresso machine

1. Remove filter from tank
2. Mix descaling solution in tank
3. Hold power and "dispense 2 shots" for 2 second until flash.
   Now in descale mode.
4. press "dispense 1 shot" to descale head
5. Run steam, about 8 seconds
6. Run hot water, about 13 seconds
7. Repeat previous 3 steps until tank empty.
8. Rinse and refill tank.
   Repeat descale sequence with fresh water until tank empty again.
9. Replace tank filter

One online resource recommends 1:1 vinegar to water solution,
or 1Tbsp citric acid/tankfull.