purple steam, greenhouse seeds great white shark

Hi guys
I haven't grown a plant in a long time or by my self before, I'm growing 4 GWSs from greenhouse seeds for clones. I hope to be able to get at least 8 clones to flower in the near future. Any I'm getting some conflicting information some say its genetics some say water pH.
I'm using rain water that has a pH of about 6.5 judging from a pH test kit I have where I have to drop 3 drops of the test solution into a vial of the water, I don't know how accurate this is. Indoor grow. Water when soil is dry 1-2 inch deep, room temp 18-21C






Thats a day and a half ago some new pics to follow

Some newer ones show current size but not steams.
Even more to follow
Looking at these I think the 1st ones where 2-3 days ago

algood

It can also be a combination of genetics and a slight pH imbalance causing a slightly darker hue of purple.