I am getting ready to install a ph controller, and I need to have a KH level of at least 4. The only test I could find locally, was test strips, and they do ppm. What is the "4" then?
And as far as ppm, I am low. How do I increase my KH?
Was looking on-line at testing equip., and it lookslike the reef/salt water has different tests. Do I need one of these?