WH can't take up the nutrients when the pH seems to be very high or very
low, I don't know what the exact numbers are, but my educated guess is 6.5
to 8.5 with the middle being the best. As with all plants, taking up
nutrients becomes less and less as the scale goes higher or lower from
their best point. Which, btw, is also how efficient one's bacterial works
in one's filter.

WH though have been an enigma around here, making me wonder if the south
finally found a way to control them, sprayed the lot unknowingly to
vendors, who shipped them north and now they're all failing to thrive?

I've got a pH of 8 in my koi pond and usually by this time have HUGH WH in
my filter, they rotted away this year. Yet ones that were put in holding
tubs with lilies and a few tadpoles lived, didn't grow vigorously, but are
green and have small babies. One of those I just recently moved to the
filter to see what happens. Salt level 0.08% and I've had WH thrive in salt
of 0.12% before. ~ jan



I've only seen water hyacinths rot in a 20 gallon container of water
from very acid water, pH below 6 caused by rain. I've heard they
don't grow well in very high pH either. I hope someone else can help
you.

I had not heard this. I'll have to do some more reading.

(Do you know where your water quality is?)