Starter - bubbles but no rise

Hi All,

So I have lots of experience making sourdough starters from scratch. I've made new ones about 5 times now, I made them in different parts of the country and I've made them all in exactly the same way and never had any problems - until now.

I'm feeding my starter, every 24 hours, like I always do - discard 80% and then add:

100g 50/50 white and whole wheat flour

100g filtered water

It's been about 2 weeks now and the starter is still not ready. It gets super bubbly like it is supposed to, it smells yeasty like it's supposed to, but it doesn't rise much at all. I'm used to waking up in the morning and seeing the starter puffed up to the point where it almost overflows out the top of my little plastic container.

Things I've tried so far to fix it - I used a different whole wheat flour to see if I could get the right organisms present, no difference. I tried feeding every 12 hours instead of 24 and still no difference.

I am worried that perhaps the wrong balance of organisms has taken root and I should just give up on this one and start again?  What do you think?

Thanks for your responses!