Yeah, ocean floor is rich & will burn seedlings. I like milled spaghnum & perlite untill seedlings go into active vegetative growth. Pro-mix is a good one if you can find it. I've used it in commercial green houses since the early 80's. But don't throw out your ocean forest. Its a great medium. Just too rich for seedlings. Most of the older sativa strains aren't as heavy feeders as newer indicas & their hybrids. Always consider where the strain originated & the growing conditions, soil, temps/humidity, rain fall, etc, & you'll better understand the growing requirements of your grow. Forgive me for overlooking the fact that you had a seedlng in ocean forest. Was stoned off my ass & was instantly focused on the 'Acapulco gold'. Haven't heard from that one in YEARS! Keep us posted on that one. Expect it to be a tall stretcher & long flowering.