In my limited experience, every tank is different. Initially you have to test and tweak a lot. It takes awhile to learn what a tank needs supplement-wise to stay in balance. Eventually, you and your tank fall into a consistent routine. I rarely test anything in my 75g anymore; when I do, the numbers are almost always exactly where I want them.
So, I'm going through the process of learning the 135g. Numbers this morning were:
Nitrates -- 5 (still edging down!)
SG -- 1.0275 (more evap than I'd expected -- added a gallon and a half of RO.)
Mag -- 1300 (perfect, after adding a lot of supplement over 3 days)
pH -- 8.1+
Alk -- 11 dKH (good number, but I haven't added any buffer yet; I know this number will start dropping soon enough)
Calcium -- 430 (about right -- looks like it'll take a couple tablespoons of dowflake [mixed in RO] per day to keep this up)
I haven't started dripping Kalkwasser in this tank yet. Still debating it in my mind, but I think eventually I will.
Mariner