“Cookies: “bake until golden brown.” The cookie sheet will stay hot after it leaves the oven and keep baking the cookies for a minute or so. If you want soft cookies, it’s better to take them out when only the edges look golden brown and let them keep cooking outside of the oven.”
....So where exactly do you think those minerals in your water heater came from?
The water heater isn't generating new filth, if anything it is filtering it out.
If you aren't getting crystal clear hot water, than you need to have your unit cleaned or replaced.
Quote from the U.S. EPA: USE ONLY COLD WATER FOR COOKING AND DRINKING. Do not cook with, or drink water from the hot water tap. Hot water can dissolve more lead more quickly than cold water.
The same EPA that tells us everyone is going to die if the temperature goes up 2 degrees?
#6 I use my flower coated hands to mix the butter in then put in the freezer for 30 minutes
#8 If it boils over you need more a larger pot and more water for that ammount of pasta. And mind your temperature, you don't need a rolling boil. Add the pasta to a rolling boil and slowly turn the heat down remembering that adding food to a pan will cool it down initially.