Why is the new growth turning purple?

Many strain that don't have purple trains in them, actual have a little purple hue when expise to cool temps. Some nutrient becimes les available at lower temperature. A plant with temps below 20 degrees can express color change at the tips of theire growth going from cool to hot during night and light exposure.. has long has night don't get below yiur 15 i would nit worry esoecialy if day time is warmer. Since it can start affect growth eventually. Try to get something to raise nightbtemos in there 20 if you can. I tiny space heater on a control timer wirks great. You make it turn in when temps are below a certain temp and turn if when it reach a proper level.. you can get the heater for around 20$ on amazon. The temp controler will be a few more bux but well worth the $ in my opinion and can even be use with a cooler djring hit summer.