Leaf underside Veins going purple

Thanks guys, I did check the genetics and know that some of the pheno's show purples. I just had been monitoring the undersides as well and was taken aback when she changed colors overnight. Ordered a PH pen so I can get an exact accurate measurement. I have been using the General Hydro Up/Down kit to PH between 6.2-6.8/7. I have a feeling maybe I'm just not exact enough and they are reacting. After looking into mag Chloroses I think I'm going to do a flush and then do a feed with only calmag and Ph'd water to be safe. Other than a slight tip yellowing and the color change on the underside she appears to be extremely healthy and happy. buds are bulking quite a bit. Thank you all for your help!

Yes it is common for Runtz genetics and nothing to be worried about. Cheers, Organoman.

It’s a Mag chloroses. It can come from many factors, light too close or too intense, overwatering, EC of the soil becoming too high. First check the EC of the soil, in most of all cases it’s because the EC is too high.

Hey friend, if you check its genetics you’ll see granddaddy purple and purple kush, so the colouring is not a surprise. I saw your diary and I can’t understand if this colour is from calmag def or just genetics, so add some calmag if you see spots, but don’t worry for these purple signs.