http://www.nationaalherbarium.nl/Crypto ... index.html
The German researchers have a long history with this genus, however, one pof the best growers was an Old American, Bob Gasser which I never met, but talked to several folks that saw his operation in Florida.
Like many aquatic plant growers in FL, simply using the limestone rich spring water and slowly flow the water through the tanks added plenty of CO2 and PO4 and a little K+.
He used sheep manure mostly in pots with sand caps, maybe some peat, the vaults (Miltitary coffins actually) were outside and have shaded sunlight.
He used copper at high levels to kill algae as Crypts are fairly tolerant of most high metal ppm's.
BTW, I few old pictures from the 1990's on the Crypt's pages, see C lingua.
The 180 Gallon tank's HC has really grown it exponentially faster this last week.
I think I will flood sometime this next weekend or maybe the following weekend.
Regards,
Tom Barr