CaMg issues after some improvements maybe?

Hello,

So I am a new member on here but I have been growing for several years without serious issues I couldn't figure out with typical forum searching. For my recent grow I made some changes to improve my yield capabilities and energy efficiency which has led to issues which I have been unable to fix even after hours researching and trying several things out.

I am growing in a room I just built for my current grow lined with reflective sheets overlapped and secured in a way to seal the room. 730Watt ion Led light. I have a 40 gallon rez with lid and cutouts for 4 plants and used old tent poles to build a makeshift trellis support. I have a water chiller I keep outside the room with lines running in and keep the water at 68 degrees. I have a dehumidifier in the room with a line to pump out to my septic. I use clay pellets and rockwool for media and have used GH for my nutrients with RO water. I have a meter for PH/EC and water temp and a second dosing meter for PH adjustments. I keep the PH between 5.8 to 6.3. For the room I did add CO2 as after testing the room its very easy to keep VPD in check with little effort and I know the potential of the light would justify at least 800-1200ppms. Temps between 78 and 82 at canopy with humidity starting at 70%ish for veg down to 45% at late flowering. I am growing 4 clones from a mother light of jah which I have grown before.

I'm sure CO2 is where my problems started. I started in veg by just following my normal routine of the light feed chart for the 10 part system for GH with double the rate for CaMg due to RO water thinning out the ec to about 1.2 up to 1.4 later in veg. CO2 starting at 450 going up to 650 by end of veg. Everything was better than I anticipated so after some trimming and training I flipped them to flower. Still following the light feed chart and keeping ec at 1.5 early flower to 1.8 mid to late flower and raising the CO2 up to 800ppm I started having issues at about week 4 into 5. Stems and stalks began to go purple and many leaves were showing signs of distress. One of those could be anything but check your PH first for lockout issues things. I knew PH wasn't an issue. After my research I was led to believe I was having an issue with Mg/P due to increased productivity from the CO2. Everything I was reading including mulder's chart show that magnesium and phosphorus go hand in hand. I tried many things over a couple of weeks but never got it right. Raising ec, lowering ec, adding more camg to the point of 5ml per gallon. I went through soo much water....not my plan at all. Luckily the plants never suffered enough to ruin the grow and the trichrome development is still crazy to see. I've never seen soo much snow and I live in the northeast! LOL Not to mention cutting out all the extra electronics cut my electric bill by 60 bucks so win there. The quantity is where I think they suffered the most. Cutting them down in a few days to week after flushing.

I did try to look into ca mg ratios and the first thing to pop up when searched is the article by Cannabis Business Times stating a 4k:2Ca:1Mg ratio. After some maths on my dry erase board I found that Calimagic which is what I have been using without issue up until now is actually closer to 3.3:1. My math using 100ppms and the percentages on the bottle would have it at about 66ppms ca, 20ppm mg and 13 ppm n and a tiny bit of Iron. Could this be my issue? Am I way off here? I was thinking of supplementing Calimagic with about 13ppm mg via epsom salts per 100 ppm of camg based on my math which would put it at the 2:1 ratio. After reading on these forms I am skeptical because most people agree not to use epsom salts with camg but I couldn't really see why if you measure out at the ppm level.

Is there something else I should consider? I've contemplated straight up throwing out my nutes and trying something else but that just doesn't make sense as I have grown with GH for years with minimal issues. I apologize for the novel but I did enjoy a rip or two before starting this and thought the more info the better for diagnostic purposes haha. I know I could go back to no CO2 and be fine but not having to run extra fans to bring in fresh air and exhaust out saves on the electric. I hate having one of the highest energy costs in the country in the state I live in.

Thanks for any input...all greatly appreciated.

Your description of your grow is awesome, the description of your plant is lacking lol. Pics of leaves and stems might be a huge help to someone who knows what they are looking for.

The top three pictures are as of a week and a half ago. Currently these are flushing and about to be cut down so pictures today wouldn't really help as they are all stressing right now with 100 ppm water. I've never really liked to flush with 0 ppm water (not sure why just something I remember being told early on in my growing) so I use just a tiny dose of the base three with my florakleen.

The fourth pic was from veg growth just prior to flipping for reference. As I progressed into flower the plant shown in the second picture began to really slow down and really showed signs of stress with the purple stems and yellowing leaves. The other three also started getting the purple stems but not so much yellowing of the leaves and ended up taller. As mentioned in the thread the last few weeks of nutrients were a little hectic as I could see that they were taking up between 30 and 50ppm every day to two so I found myself changing the whole rez a couple times a week. I tried to just add camg (up to 5ml/g) but it didn't seem to help and I quickly became concerned with the actual ratios at that point because although I can see a massive decrease in ppm I have no idea what was actually being taken up. (I mean potassium for sure but what else and in what quantity) I also was aware that at that point Ca would be way too high especially in mid to late flowering so I just changed it frequently. I would have done a lot more trimming and training but as the issues crept in I wanted to avoid any additional stress so I just kinda let them do their thing for this grow after the initial topping and trimming during early veg. Ultimately my goal would be to have a lot less vegetation to allow better airflow/quantity capabilities and many fewer branches.

I thought I would add a pic on the monitoring/water chiller just so you know I take my water quality seriously HAHAHA
I have a 50 gallon sealed drum not pictured that I keep RO water in using a float so it can collect over time as I use it. One 44 gallon trash can used to drain the system/dehumidifier into my septic using pumps and another 44 gallon trash can used for mixing nutrients. To keep roots from getting into my water chiller/drain lines my wife was brilliant and found some super fine nylon meshed bags she was using for washing our newborns reusable diapers that I put my pumps in inside the rez so water can flow but the roots don't grow through it. (I used new bags lol)