I would like to say that what is the coral crushed used.
I have check around my house (in France) what is crushed Coral sold for sea fishes aquarium.
Most of the time, it is in fact "Maerl".
Maerl is a collective term for several species of calcified red seaweed. It grows as unattached nodules on the seabed, and can form extensive beds in favourable conditions. Maerl is slow-growing, but over long periods its dead calcareous skeleton can accumulate into deep deposits (an important habitat in its own right), overlain by a thin layer of pink, living maerl.
It is very rich (in its components) in Calcium (Ca), Magnesium (Mg), Iron (Fe) and few trace elements.
Mg is an important part of Chlorophyllum (word ?)
Iron (Fe) is important for the photosynthesum with (N)
Ca is also important for the growth of the plant...
On the otherhand, you can also find true crushed coral (I thought it was prohibited) that is "pure" Calcium carbonate. Too much Calcium may leed to the plants "Sarracenia0" noted.
"Pyro" may use Maerl in fact mixed with other components and give a suitable mix full of all nutrients for his plants. My question is also how long will this fast growth last ? Few month, one year ?. How will it old ?
Many experiments interested to do "Pyro"...
This is some ideas to discuss...