My plants are beginning to have some issues, I have been using the cheap vial and formula to test pH (i know, I know..got a real meter coming) On that same note, my nutes (Nectar of the Gods, Organic) lacks a good amount of CalMag. I am in week 5. Let me know what you think. There is some twisting, some brown/yellow spots, some tips drooping. I don't really know which route to tackle first.
No input? Well, I decided to just do a pH'd flush, was getting 5.5pH out and 1400ppm. So I think I have a little of both problems :/
You're wise to flush, at least doing so is your number one, best action to take. Most noobs never realize that the plants roots produce the ph of your substrate (5.5 ph run-off, 1400 ppm's, are to much). Your ph (in theory) is probably lower than that. Next water through you may need to flush again. Let her dry and flush again, sometimes it's necessay, so I'd keep a constant check on run-off (assuming you're in soil). Study this chart ... http://boards.cannabis.com/attachments/plant-problems/281235d1325194867-brown-spots-some-twisted-leaves-some-tips-curled-down-phchart.jpg
Your girls are indeed expressing a Mg and Ca deficit, and a ph at 5.5 locks out P, K, Mg, CA, and Sulfur ... it's good that you noticed the damage early on. I would correct the root-zone ph and add a complete fertilizer at about 600 ppm's to start, as long as your ferts are "complete." If not complete, get one with all the Macro's and add Cal/Mag.