I have never seen a deficiency on a land race so I guess you are spot on there, they do more with less food. The Epsom salts work fine, I used to use half of the recommended tsp per gallon and only one little watering with that has always been sufficient to see a clear difference within a few days. I was told that dolomite lime can take a few months to become useful for Mg, and was recommended to cook my dolly mixed soil for at least 12 weeks. Since switching up to the gypsum and oyster shell I will feel cool with a four week cook and can probably get away with less. Bro I totally overdosed an outdoor crop on dolly back in the day, I can definitely relate to 'wish I never got this stuff'... After this light Epsom salt feed give them a few days, they should go greener feom the veins of the leaves outwards at first... I love watching the recovery phase. Cannabis has an awesome will to not only live, but thrive.