Your tank's gravel was not the issue nor was it running out of
nutrients.
You will need to uproot and prune plants every so often.
I work a section at a time, in 1/4 chunks each week.

Some plants, Crypts, swords etc are trimmed, runners removed etc.
If your tank stalls and you have keeping up on the CO2, (20-30ppm) and
adding traces, you need to look at the macro nutrients.
Running out of these will stall a tank big time is the common cause of
any "stall".
Try adding KNO3, K2SO4 and some PO4 next time.

When a tank gets well chocked with plants, the amount of nutrients
removed is quite high and the plants will overwhelm the tank unless
you prune the plants and or add the nutrients.

Yes, Flourite/onyx/red etc is dusty.
I rinse 1/2 a bag at a time in a 5 gal bucket, swish it around a few
times and decant. I do this 3x per fill. That's it.

Java fern gets most of the nutrients from the water column. Another
sign that it's the macro nutrients.

Anyway, I thought this was pretty bizarre. Anybody out there have
experience with Flourite Red?

I've heard it's dirtier. I use the flourite or onxy sand though.
Not sure why. Ask SeaChem.
Regards,
Tom Barr

Marc