Purple Stems?

So I have a batch of vegging plants that the stems have turned purple. I know this is not a genetic trait since I have been growing this strain for 6 months! Ok, please no replies saying that it is just a genetic trait! There growth has slowed, and have a general unhealthiness. This is the first time I have run into this problem, and I hope it is a simple problem. Anyone out there have any thoughts on this?

ph lockout (most likely), P def(maybe, be careful if it is locked out) or less likely cold nights (

i am having the same problem right now, and just asked that question in the newbie section, hopefully ill get some replys there

ph lockout (most likely), P def(maybe, be careful if it is locked out) or less likely cold nights (

You may be on the right track with the PH lockout, I have had problems with my ph dropping lately. If the problem is a ph lockout, what steps should I take to relive them? I am thinking a foliar feed would work well...right? Hmm.

just adjust the ph to the proper range without adding more nutrients - foliar feed may help but will not fix the underlying problem at the roots.

Thanks for the chart csharper. I have been looking at charts like that one for 6 months now and have never quite figured out the best way to regulate PH according to the chart. It seems like to balance the ph the best, it would be good to start 6.0 and let it drop down to 5.6 during the week "hydro". then your plant would get the full spectrum before the next nute change. Any thoughts?

correct me if I am wrong but the ph should go up as the acidic nutrients are depleted...

you should just get some ph drops and keep your reservoir at the optimum always. No reason to allow fluctuation if you can help it.

LOL, yeah man, with GH products I had my ph dialed. Every few days a couple drops of ph down and problem corrected. but now with Advanced Nutes, the ph needs to come down, then after 4-5 days the ph starts to drop! So then I have to toss in some PH UP! So I am going to start cleaning out everything in between res changes every week with Flora Kleen, and try to get out most of the left over salts, and see if that helps correct this PH balancing act. Thanks for the thoughts csharper!

i have a similar problem but i was told by someone in the newbie section that its completely normal so i didnt worry about it....My stems were just purple/redish though they look perfectly healthy other than that.

Yeah, like I said before though...It is not a genetic trait of the strain that I am growing. This change in color is due to a problem that I am linking with stunted growth. I have changed out the res with fresh GH nutes and have the PH stabilized, when I see change I will update this thread...Thanks for the responses everyone...