Coco is not my favorite medium. If you search peat vs coco on google, I posted a blog on why. From your original recipe, I noticed a lack of Ca in the form of gypsum so as not to raise pH. That could have contributed to some of your issues as well as lacking S for terpene expression (hence why gypsum is great). RO is not ideal due to it's lack of buffering capacity (water wants to be bonded with other minerals).
All that being said, many growers are using coco successfully so it definitely is possible. If you want to experiment and mix your own mixes then a soil test is your best friend to determine your getting the right nutrients in the soil in the right ratios.
All that being said, many growers are using coco successfully so it definitely is possible. If you want to experiment and mix your own mixes then a soil test is your best friend to determine your getting the right nutrients in the soil in the right ratios.