From what Squidy told me on my thread, brown spots and slight yellowing on leaves could be cal-mag deficiency. Do you know what levels are in your water?
Cheap alternatives if your ph meter is broken are litmus paper strips or an aquarium ph testing kit to test your water (and nutes if you're feeding) and runoff. I'm sure one of the others will advise on better ph testers
Other than that slight problem, they're still looking great :smokebuds: