My milk kefir grains into the second week. They are converting 600ml of milk every 2 days.
I change the milk over every 2 days because I like the sour taste that comes from leaving it to ferment for a little longer.
The results could smoother result if it was harvested daily, but I have found a 2 day cycle works best for me.
The grains are whiter and fluffier than when they arrived and have increased slightly in quantity but not enough to have 2 batches yet.
The pic doesn’t do this hard working team justice.