This really is the best answer if you want to test frequently with quick results. Aquarium test strips usually use ppm, and the number you’re looking for is less than 3 ppm, but 20 ppm is considered acceptable. There are many test kits that will show for less than 10 ppm and 10 to 25 ppm. If you’re in the first range, you’re pretty much okay.

It also isn’t a bad idea to send your water for regional testing, too, so they have another endpoint in their system for testing (or if you’re on your own well so you know if it’s safe).