, and Mag, can be tested monthly unless you are unable to configure a consistent expected reading from dosing, then bi-weekly would be best. Typically you shouldn't see any NH3
readings 4-6months after your cycle and NO2
isn't detrimental to livestock for the most part. At best I would test these monthly, but every couple months or so would be sufficient. PO4
can be tested at best bi-weekly, but monthly is also sufficient. I do not see a point in testing oxygen or copper unless a problem makes itself present. Your pH should be tested at the very least monthly, but better off bi-weekly.