I heard the same thing as @Crashdog. I am growing purple express auto fem and I just recently moved from 24hrs of light to 20hrs on and 4 hrs off. I leave my a.c. on while the lights are off and it shoots the temps down 10 to 15 degrees for 4 hrs. I just started doing this so I can't say much else. However, I do have a purple strain and it's supposed to get purple. I am doing this as an extra precaution to make sure i get purple as well as saving a little energy.The pics are really sweet though. Beautiful colors present bro.
I have had my lights on 24/7 from the start, I have kept an eye on temps and it has never gone over 29 or below 20 so Im not to sure if it is the temp that makes the colour.
Thanks for the reply and good luck with your grow.
I've also heard that bringing your night time temperatures down can help with color but for sure it has mostly to do with strain. You've obviously made an awesome choice on strain because those colors are wicked. I have to admit, Somango is not a strain that I've heard of. Nice clear shot of your girls too, congratulations on the way they are turning out.