you may have done nothing wrong at all. I've heard that elderberry leaves a
nasty scum behind in ferments and maybe that's what you're seeing.

How about an assist from one of you experienced country winemakers? I can't
really speak authoritatively on this topic.

I've not made more that 10 or 15 country wines so this is just a best
guess. Others have said Idophor is probably not an issue with wine in
general when used in correct ratio's and it makes sense so I doubt
sanitation is an issue. I wouldn't be concerned about the sulfite
level at this point either but would suggest you throw away those
campden tablets and get some potassium metabisulfite powder, it's a
whole lot easier to use. You needed a jackhammer to crush the campden
I had when I started making wine.

As to sanitation, with grapes there is a term for everything else that
gets fermented, MOG. Material Other than Grapes includes dirt, bees,
spiders, webs, you name it. The pH of musts in general protects the
must, a lot of really nasty stuff can go into the fermenter and it
still comes out wine. With that said, I would agree that the wine is
not lost. If the scum looks or smells like mold I would be concerned
but other than that I would not consider it a big deal yet. If it
scared me I would remove it by racking or overflow if that is possible.

You already have good comments on nutrient deficiency, that's pretty
common in country wines. I always add nutrient, there are many brands
so just use what your supply house handles. I like Yeastex and Fermaid
and do use DAP when I think it's called for.

I haven't seen much said about fermentation temperature. That could be
a big deal. At least when getting it started you may want to get the
must up to 70F or so. Country wines in general take more care and
feeding than grape wines, they emulate meads in that respect. If the
must is cold, move it or get a cheap heating pad from the drug store
that has a normal three stage switch, no timer. They are getting
harder to find.

Joe