What is the best way to manage the cooling water for a K40 laser to prevent it from becoming stale for lack of a better word? Obviously distilled water is preferred, but I’ve also read about people using tap water with some type of sanitizer or coolant included that will prevent it from developing algae.
I would not add anything to my distilled water other than the algecide at the rate prescribed in my blog.
You can buy a conductivity meter and test your water which can give you a hint as to when it is too conductive.
Be careful with tap water as it also could have additives and high in iron. If you have water conditioners that can also increase the conductivity.