Buckwheat Starter

I’m in the middle of making a Buckwheat Starter. So far so good. Seems to be strong and steady. Two days in and within 24 hours the first feed had a strong fermentation and after the second feed it had become active overnight. Will give it a few more feeds just to make sure it’s stable enough to make bread and aim for a weekend bake. There is one factor i’m not sure about. The top of the starter turns a purple hue which disappears when stirred and isn’t present when fed. But after a few hours the purple hue appears on top of the starter again. I’m thinking this is the nature of Buckwheat when hydrated and comes in contact with air. However would just like to make sure it’s nothing else. When it comes to baking is there a way to avoid this happenig to the dough or should I just appreciate it’s Buckwheat and enjoy the resulting bread with colours and all?

I’ve got a recipe forming in my head and here’s the plan…

*** 100% Buckwheat Flour**
*** 5% of the flour + 5x it’s weight in milk to make a tangzhong**
*** Water + Cia Seeds (What is a good total hydration for Buckwheat? After i’ve taken off the milk for the tangzhong i’ll use the remainder for water + cia. How much cia for water to make a gel and how long should it rest for?)**
*** 1.8% salt**
*** 1 tablespoon olive oil**
*** Starter % will be determined depending if I wish for a shorter or long bulk ferment then shape and final proof**

Please feel free to chime in with ideas on how this recipe can be tweaked and improved.