I'm not familiar with Bio Bizz, but even small amounts of ferts can cause probs for seedlings. I give NO ferts till the seedlings have 3 sets of leaves. Walmart has this seedling soil which is pretty much pure ground up peat, no ferts. You need to post a pic of how they look now, after you worked on them. Damping off is a fungus that has already done it's damage. The green leaves look ok to me. Don't fuck with the plants too much ! If you're lucky they might all recover !!! He,he,he