Q: What is a good temperature for a tartaric acid-based descalers? I know that sulfamic acid-based descalers are used cold and that citric acid-based descalers need heat (50-60C). But what about the sulfamic acid-based descalers for aluminium boilers?

Traditionally, people used a mild acid for aluminum. In particular, the recommendation for Bialettis and such was to use 50% vinegar, keep the vessel hot, and let it sit a few hours. You can use 25% lemon juice (about 2 tsp citric per liter) for the same strength. I'm not sure what the recipe for that strength of tartaric acid is -- tasting will give you a good idea.

I have a good idea as far as the strength is concerned (20g/l for mild use, up to 50g/l) - but what about the temperature? I'm asking because I need reasonable defaults for a descaling program.