Slight yellowing

 Girl Scout Cookies Extreme(ILGM) started flowering at 3.5 weeks, I had been adjusting water to 6.3 ph. Prior. I have LST to this plant have about 15 main colas going. (Great experiment) A few fan leaves getting pale green, one started get a little yellow middle of leave. Going great but getting nervous about new developments. Have 3 new meters coming, need digital ph meter, parts per million meter. Have good meter for water need good 

soil devices. I think ph may have gone too low, if so best way bring back up. Will try send pics. Thank You…

I water my plants with a ph of 7ish.