Orange/Brown spots and marks

Hi there, i'd go more into the direction of calicum when it comes to the rusty spots. The leaves look pretty dark green, so i hope that you're not feeding it a bit too much (or were at a point). Do you use tap-water and if so, do you happen to know if it's soft or hard? Do you add any calmag? I honestly don't really like the liquid PH meters, as they're not very exact. Simple to use and maintain, yes, but not very exact. I really would suggest to invest in a decent PH meter as well as an EC meter like the ones from bluelabs (the pens are great). Yes, it is an investment, but only then you know how much you feed your ladies and if it can be absorbed properly. Especially since your grow mentions "soilless" it's important to get the values right, to keep the plants healthy and happy until the end. happy growing!