The foam in the pot is a completely naturally occurring outcome when using gluten-free ZENB Pasta. Quick science lesson: Without gluten, the proteins and carbs found in legumes are not restricted from reacting with the water, which is what causes all the foam to form at the top of the pot.
You can simply skim off this completely naturally occurring foam when draining your pasta, or just turn the burner down to a lower, rolling heat while cooking (which is better for cooking pasta anyway!)