For early-season germinating in plastic cups, I use something like FFOF that has plenty of Ca and Mg out of the bag.
For general ferts, I use the Dreaded MG Blue Crystals of Death, applied as a weak solution w. every other watering. Of the major nutes, it lacks only Ca and Mg.
This year, established plants will go into composted green mulch (
http://tanksgreenstuff.biz/recycled-and-organic-landscape-materials/) mixed with local soil and a dash of perlite or coir. The local soil is nothing if not loaded with Calcium. An occasional dash of epsom salt should provide all the Mg needed.
If I did need a CalMag fert, I'd go to Fleabay and buy a few small envelopes of Ca and Mg nitrate (or chloride or acetate or gluconate or... ) and mix my own for a
tiny fraction of the outrageous price charged for any of the Ca/Mg products found at the local hydro store.
Yea, I flush, but only when it's warm, and only when the plants are big enough to pull much of excess water out of the soil fairly quickly. I tried a cool weather flush earlier this year (Some idiot mixed too much moo poo in the soil) that nearly killed several plants.
Never done a PH, although it might not be a bad idea.