When you read instructions for descaling, usually is says something like "Run the pump so that 8 oz solution comes out of the group and then turn the machine off and let it sit for 15 mins." Then turn machine on, run 8 oz. through steam wand and turn off machine and let sit 15 mins."

Then it says something like "Repeat until all solution has been used up"---
My 1st question is:

Does that mean to keep repeating the "run 8 oz then turn off machine and let sit for 15 mins" (alternately through group and wand) OR does it mean to run all the solution through the machine after the 2 15-minute prior sessions?

It takes a couple hours doing it the first way but I did repeat the 15-min things over and over until solution was used up last time (64 oz reservoir on my machine means repeat about 7 times--to leave enough solution in reservoir not to run the pump dry, otherwise it would be 8 times). Is this correct? Or am I spending an unnecessary hour and a half on this? It's not clear in the instructions I have read.

My second question is:
Should the machine be turned off while the 15 min sittings are occurring? Often I read nothing about turning the machine off but a source I read for the Gaggia machines says to turn it off while sitting (maybe b/c of the aluminum boiler?).
???

Thanks.

Repeat in 8oz units until the fluid is gone with an interval to allow the descaler to work.

On my machines I repeat until the descaler is clear, not blue, with the machine on at 30 minute intervals and 2T / qt concentration. So far so good.

Can't comment on 'Turn Off' with the aluminum boiler.