Are you watering everyday? I'm inclined to think even in that big of a pot watering that often should be a no no? I don't think you need to water but every 3-5 days or so at this point. I was watering every 2 or 3 days at the point you were at maybe changing over to two days but thats with 11L pots and I'm only watering 3L of water per watering. I don't think the fluctuation in ph maters as much in soil (watering 6.4, 6.5 and 6?) but I would try to keep the number the same every water if you can help it.
Looking great otherwise! Can't wait to see the end results :Sharing One: