Ahhh right............ so zero Ec "RO"................ before using carbonic acid = rainwater, used RO from my own RO filter................... as my nutes like most, are acidic, i used to buffer the RO with 250pp of alkaline tap water........ so this helps off set the acidity from the nute in put @Ec0.9 flower time............ if you adjust this buffer right, as you go through the grow, you should not need to add Ph down................. in un buffered, zero alkalinity RO, adding nutes, you will need tp raise the Ph, Ph up, after making the res Ripp mate ??.....................
from the time line and visuals of the plants, it was later than day 20 flip to 12/12, i would have though............. you just moved the zkittles to the 12/12 tent with the other nearly finished plants then Ripp ???.. the fully flowered plants in the day 21 pic. plants at switch to 12/12 in the day 21 update, are only just at the 3rd internode, is that when you usually go to 12/12 then Ripper my man.............. root has barley filled pot by then maybe ?/......ALR