My sourdough starter split in 2 on the 3rd day. What should I do? I have fed it first after 24h and it grew nicely. And on the 2nd morning after I woke up I saw this:



Should I keep the upper half? or simply start a new batch?

I have used the following formula: 200ml water, 200 gr 550 flour, and kept it at about 25 degree celcius.
Sourdough during the first few days can show pretty erratic behavior. I wouldn’t worry, just stir and feed as planned. Continuing the culture with just the foamy top would probably also work. 

Reasons to start over would be visible mold (fluffy or colorful spots) or if there’s no bubbling. Neither is the case here.