Salifert and Nyos test kits with Aqua Forrest dry Mg and Ca along with liquid alkalinity.
I do a >95% waterchange 2-3 times a year to bring the micronutrients and trace elements back up to normal levels. System volume is currently less than 15 gallons, so this is simpler and easier than trying to manage testing and dosing.
I tend to use a combination of Hanna, Salifert, and the API test kits, as I am slowly piecing together my master kit of strictly Hanna and Salifert. For 2 part I really like using B Ionic, and in the past have used Seachems 2 part fusion.