55gal Res not fluctuating is this normal ????

I have used 55 gal ebb and flo system for 12 or so waterings. I use rockwool and hydroton.
I mixed how I wanted it and PH is where I chose. Question is: Why has my res PH,PPM,EC not fluctuated but just a LITTLE ??? Lets say 1110 to 1120 and 6.3 to 6.4. Small changes ???? Help me tune this in I am new to hydro. I am pretty knowledgeable
with what I have going but need to get a few things tuned in. Come on by and check it out and I hope to get some love on this question.

I am guessing the plants are small and are using very little nutrients right now. Nice journal BTW.

My plants are days into flowering and went in FROM veg at almost 4 foot !!!!!!! This is not the problem ?????????? They feed 3 time a day 15 minute flood of 6 buckets.

Got's me then. Maybe they are just going through a change and are adjusting to the light right now causing them to not use as much. I'll read around and see if I can find anything for sure.