I'm not sure how much RO is better than britta filtered water as I don't have a tester yet (getting one soon I've beenkicking myself for waiting this long) but I have 200ppm tap water and that made the ph climb a ton if I didn't let it sit 24 hours and even with sitting 1/4 to 3/4 a point for the first 36 hours in the res... I've found the britta almost clompletely eliminates the urge to climb even without waiting very long to drop it in...

I'll let you know what the ppm ratings are for tap, britta, nuted food once I get the tester

I'm pretty sure WeedHound had a similar experience on the climbing res too and she felt it was related to growth and waste as well

As long as your girls are looking healthy and oriented properly toward the light you should be fine although I did notice that if you are going to raise the nutes that the plant seems to like it better for much weaker doses of food more often I try just really pay attention to the fan leaves cause in hydro and aero the signs are usually fast enough so that you can atleast remember what you changed ;-)

I'll post back when I get that tester lemme know how it's goin cyc