I figured it was close enough to spring (southwestern Arizona, zone 10-11) to dress
up my little pond a bit and maybe avoid some of the dread algae bloom, so I bought
some water lettuce, hyacinth, mint, and duckweed from a company I've dealt with in
the past. The plants arrived within 48 hours of shipping (the company is only 130
miles away) and appeared healthy. I plonked it all in the pond and things were good
for about two days.

Day three and I went out to a pond that looked like it was covered with ash. All the
duckweed is snow white. The edges of the water lettuce are withering. The hyacinth
is still greening nicely though and the mint is unbothered.

My test kit shows all my values are within normal limits. My GF, minnows, and
turtles are all fine. Temperatures haven't sunk below the 40s at night and my pond
temp is warm enough that the fish are frisky and the turtles active. I don't see any
sign of aphids, etc, though I haven't used a magnifying glass.

Any ideas?

Gabrielle, heading out to remove all the duckweed