Good to hear your experience with Physan did not affect the amaryllid seedlings. Our posts must have crossed in the mail. Maybe that Crinum had another problem. Thanks, Fred! Ken --- On Wed, 2/1/12, Fred Biasella <email@example.com> wrote: As a matter of fact, I had the same experience with seedlings as Ken did. Just recently I got some seeds (nerine x amaryllis & amaryllis x brunsvigia) ... Very shortly after they sprouted (100% by the way) I noticed some algae starting to form on the growing media ... Right away I thought Physan 20 should help, and it did. I water my plants with rainwater only, which is rather acidic in the Northeast and since algae and mosses love acidic conditions, the only conclusion was to make the water less acidic by adding the Physan 20. The seedlings are growing nicely and starting their second leaf stage, but I do keep and eye on the algae and as a preventative I give them a soak once a month with the Physan. .