My starter is having multiple cycles of rise and fall
I'm feeding my 3 weeks old starter twice a day. My kitchen is around 80ºF, and my mixture is 80g white organic flour, 20g rye flour, 16g mature starter, and 100g room temperature water. Six hours after feeding the starter is resting at its peak for just half an hour, then collapses and after 1 hour and a half starts rising again to its peak. Is this normal? I'm doing somenthing wrong? also what can i do to it takes longer (12 hours not 6 hours) to its peak? a small amount of inoculation or colder water?