No, I believe it is inert. It has high cationic exchange capacity, that's it.
Just a quick clarification; Flourite (#19) (CEC = 1.7) does not have a high CEC like the Montmorillonite clay materials such as Turface (#16) (CEC = 29.8-41.1) or Safe-T-Sorb #7941. Although Flourite has a relatively low CEC it does contain a lot of mineral nutrients essential for healthy plant growth; although the low CEC would bring into question the ability of Flourite to release those minerals to plant roots.
CEC Values of Various Substrates and Additives (per Planted Aquaria Magazine issue #2)
75 Gallon, 2X55W AH Supply CF 8800K, 1XMarineland Doublebright, 2X Marineland 350 Magnum; 45 Gallon Tall, 96Watt AH Supply CF 6700K; 30 Gallon Long; Fluval F&P 2.0 36"/46W; 20 Gallon, 1X26W AH Supply LED kit; all with Press. CO2; (Calcined) Montmorillonite Clay
Greater Seattle Aquarium Society (GSAS)
Last edited by Seattle_Aquarist; 11-21-2013 at 02:59 PM.