That depends on your personal taste. The more times you press the carbonation button, the more flavor there is in the water. We recommend you to bubble 3-4 times.
Yes, that is perfectly normal. As with a good beer, some foam may form in the bottle during bottling. This happens mainly with new cylinders and depending on the local water quality and the type of device used. However, this is not a problem. The foam settles after just a few seconds and is then completely gone. Please do not remove the water bottle from the bubbler until the foam has settled.
There are several ways you can tell if your CO₂ cylinder is empty. First, please make sure that the cylinder is screwed in correctly and, if necessary, tighten it again by turning it to the right. If there is still no carbon dioxide in the water and you don’t hear a hiss when you press the button, the cylinder may be empty.
To check this, you can simply weigh it with a household scale. The weight of a full SodaTASTE cylinder is approx. 1200g. An empty cylinder, on the other hand, only weighs around 760g.