Back with an update after some weeks. I still haven’t figured my issue out completely. I’ve slowly bumped ec down waiting to see a decrease showing me the plants were eating more than drinking, in which case I planned to gradually increase the ec. I made it all the way down to 0.7 ec and saw no decrease in ppm. My big issue here now is my ppm stays the same, water goes down and ph goes down from 6 to 5.4 daily. I am looking for ph to rise and plants are eating and I have yet to make it happen. Unfortunately my time has run short I have to start flower now or I am in some trouble with height. With that being said Mark… when you switch to flower do you typically start running b1/b2 immediately after switching to 12/12? Or do you continue v1/v2 for the first week on 12/12? The girls look healthy I’ll have to upload some photos tonight. Just not perfect and thriving to my liking 
If your Ec lowers your Ppm should lower with it. Ec/ppm are the same things just a different form of measurement. It’s like saying Celsius and Fahrenheit same thing.
I change to B1/B2 the same day or within 2 to 3 days later. (Normal I try to make the switch same time I need to make more nutes)
Thanks for the reply Mark! I’m aware ec/ppm are measurements of the same thing. I’ve been reading ppm so I can more easy tell what the water is doing. A 10 or 20 ppm drop won’t show on the EC but ppm will show it. I’ve done a lot more digging into hydroponic water chemistry this past week. My ph should rise as the plants drink. It never has. Which has be super confused. My water level should lower, ec/ppm stay the same and ph should increase… my PH is dropping from 6 to 5.5 every 12 hours. I suspected possibly bacteria like you had mentioned so I’ve been using current culture uc roots for the past week. No change. I’ve decided to live with it and chalk this one up as a learning experience. Well see how flower goes. The plants look better than most hobbyist grows I see but I was really shooting for perfection. I’ll keep some updates coming as time progresses!
5 days into flower and I think we’re making a turn for the better. 1.3EC seems to be the sweet spot right now. Plants are drinking, ph is increasing as they drink and EC is remaining the same. Canopy starting to fill in nicely
Looks really nice to me… If they were my plants I wouldn’t do any trimming until Day 21 of flower now…
On day 21 go in hard
What does it look like under the net?
I planned on defoliation about day 20 myself so that sounds good! I hit them pretty hard before flower mostly down to 2 nodes. I left a couple short stalks I wish i hadn’t now but we’ll see if they make it to the net during the stretch. I plan to add a second layer of netting today so I won’t have to tie up any colas down the road.
Looks good under the net also…
Day 20 or 21 no different 
I have the same rdwc system and I’m have the same problem you had going on. Water level drops, ppm stays the same, ph drops. I keep lowering the ppm because I was told these systems need a lower ppm if your not using current cultures cultured solutions nutrients. Im running 20 gal total and have to add about 1 gallon a day. I add just ro water to bring the ppm down and the ph back up. I’m at 730ppm on the 700 scale and 5.8-6.2 ph
The conclusion I came to with floraflex in this system… the ph is going to drop using v1/v2. I found my ppm stays the same, water level goes down and ph decreases. It made no sense to me but I eventually accepted it. Once I switched to bloom my ph rises as it should, water level goes down and ppm stays the same. Sweet spot for Mr in veg was between 1.0-1.4ec. Hope this helps! I’ll be posting up update here soon. Currently week 2 of flower. Another suggestion I will make- run a sterile system. Forget myycorrhizae and beneficials. I’ve been using UC roots in combo with a water chiller and the plants seem much happier. I feel the beneficial caused me more headache than anything.
Got mine to finally work like it should, ppm stable oh goes up a little each day. I’m using advanced Nutrients, I’m running at half strength on full-grown plants. I guess this system is designed to help the plants uptake nutrients at an accelerated rate and so is advanced nutrients. I’ve found my sweet spot to be 700-720 ppm on 700 scale. That causes it to drink a gallon or more a day, ph up, ppm stable. If I go to 730 it will cause it to drink 1 or more gallons a day, ph drops and ppm will go up a little bit at a time as water level drops.
I called advanced nutrients and current culture and they both told me that I was running too many nutrients for the system and to try it at half dose and see what it did, ever since then I think I’ve been fine and knock on wood…