honestly italian, i don't know what the ph is, i have no meter to check it.

and maxrun, if the how of it is really what you want to know,
the easiest way is to have an extra bin to put the plant filled
lid from one bin onto the extra bin while you then empty and clean
the original bin. then just put the plant filled lid back on the
original bin.
if your question is more toward how often, i'd say every 2 weeks
to every 10 days.