Sourdough Starter Helppppp

[offthebeatentrack]

Hi, wondering if anyone here can advise.

I'm now into my third week of trying to make a sourdough starter. Initially I was keeping 50g of starter, and feeding 50g bread flour/wholemeal flour mixed, and 50g warm water.
I've never really had much activity. For the past 3 days I have been keeping 25g of starter and feeding 50g wholemeal flour and 50g warm water. Two days ago, the starter doubled in size within 6 hours, lots of bubbles etc and was looking good. However yesterday, after the same feeding method I've had no activity except a few small bubbles.
What am I doing wrong? Should I persist with this starter or try to create a new one?

I'd say persist! I think it's quite normal to see some action then a lull.

You've followed all the instructions I take it, ie not in fridge, lightly covered, somewhere not too warm but not cool... You could leave the water out overnight to get rid of any chlorine, that might help? I don't think I used warm water, only room temperature when I did mine.