Just received the following reply from GH Tech Support...
"Hello,
There are no living organisms in Flora Series. It is perfectly fine to use H2O2 with it.
Thank you,
Jesse Pennington
GH"
So, I guess that H2O2 is fine to use in the GH Flora series after all, which I like to hear.
Would anyone here be able to explain exactly why they think H2O2 shouldn't be used with GH Flora series nutrients? I'd like to hear back from the "growers in the know" before I start using it again.