That's purple?
Is it cold?
Oxygen deprived?
Sent from my SCH-I545
Purple this young can indicate a possible potassium def too.
That's why...the cold "will" lock out P and turn your baby colors...I do it on purpose in the last 2 weeks of flower to bring my colors out...more than a 15 degree sudden drop will cause the P lockout, I mean unless you got 85 degrees and it drops to 70, it's gona be fine...but, dropping from 72 to 58 will cause the colors from P lockout...JMO...peace...It did get cold lost power for about a day due to weather. Got down to 28 in my house about 60 in my grow room.