nice! they look a whole lot happier and healthier since u switched not only the containers, but medium as well, Ferti-Lome is good shit! i mixed a bag of that with a bag of Fox Farm Ocean Farm and have had a great time with it, MG sux, hopefully we can agree now =) water retention has nothing to do with nute burn or not, water retention just applies to how much water is retained or held within the soil. if you had shitty water retention that would mean your medium would not hold a sufficient amount of water, if you have to much water retention it means that water will stay in for a long time, leading to root rot or fungus. Nute Burn refers to nutrient uptake, if it takes in too many nutrients at one time it will "burn" the plant. keep up the good work, and stay stealth =)