I have recently noticed that my starter was not rising particularly high. It frothed fine, but the actual rise wasn’t very impressive. It was still raising the bread, but I felt it might be somehow losing its steam, since it often spends 4-5 days at a stretch in the refrigerator. I refreshed it several times in a row, but it still wasn’t rising particularly. Remembering a similar effect from when I was trying to get my starter going, I decided that instead of refreshing at 50% water and 50% flour, to change it to 67% flour and 33% water. Sure enough, the next morning it was rising brilliantly. I may need to switch to using slightly less hydration to get the effects I am looking for.