Gorgeous plant, Rick!
I started adding Epsom Salts to my fertilizer solution a couple years ago; but, for only February through October. I feed very little from November through January and the hydroponic feed I use already has Mg in it. The Epsom Salts made a HUGE difference in the green look of my plants by the time fall rolled around. Everything looked so much better!
Also, during the period of October through April, I only have R.O. water available to me. From May through September, I can also use water from a nearby stream, which I do for the deep waterings. I water one bench each day with the stream water, which has low levels of disolved minerals in it of course. Then, I mist/spray the entire greenhouse, including the bench that I just thoroughly watered, with the "plain" R.O. water. The thing is: the "plain" R.O. water does have a tiny amount of nutrients in it because I add them to a stock tank. I used to acidify my water until I sealed my concrete storage tank. Now, I don't have to adjust the pH; but, when I started using the pure R.O. water from the tank, which was NOT adding any lime though leaching from the concrete, my plants turned a sickly yellow!!! It was really scary!!! I panicked.....calmed myself down and really gave this all some serious thought. I decided that the untreated concrete tank was helping a bit by leaching lime into the water. I used the R.O. water as a fast enough rate that the water did not get too much lime to cause problems. Plus, when I feed my plants, I make up a small ~10 litre pail of concentrated fertilizer stock, which is almost all used up by the time I'm finished spraying all my plant with the diluted solution, made possible with the use of a Dosmatic fertilizer injector. I couldn't bear to toss out the leftover stock solution (I paid good money for that fertilizer!), which would be about a ~litre or so, each time; so, I was in the habit of tossing the leftover into my 17 gallon, clear stock tank and that turned out to be a good thing. The combination of a bit of lime from the tank and the bit of leftover fert mix being added to my clear stock solution which I used when I was not fertilizing, provided enough "extra" to keep the plants happy.....as long as I also kept up with a regular fertilizing schedule as well.
Once I sealed the concrete tank I also decided to stop adding leftover fertilizer to my clear stock tank....and my plants went yellow at an alarming speed! Of course, the storage tank remains sealed; but now, I never use 100% clear water in the clear stock tank. I always add a bit of fertilizer to it so that the plants never get only 100% pure R.O. water.
When I grew in the basement I also had an R.O. I stored my product water in 17 gallon Rubbermaid garbage pails; but, I always removed a couple gallons and added raw well water back in. The raw well water was high in minerals, especially calcium and my orchids grew like weeds. Eventually, I stopped adding the bit of raw well water to my R.O. water storage pails and my plants turned a sickly yellow. IMHO, pure R.O. is NOT good. It must have small amounts of nutrients added back in.....even if you feed regularly with a good fertilizer. After all, while rain water is very soft, it is not pure water by the time it reaches our storage bins...or the plants in nature for that matter. Thinking that rain water and R.O. water are basically the same thing is a big mistake.
