Typical working concentration 1.5-2.5 g/L in plant tissue culture media up to 10 g/L in microbiological media. Phytagel(TM) requires the presence of cations (especially divalent) for gelling to occur. Concentrations of calcium and magnesium contained in most plant tissue culture media are typically sufficient for gelation. Low-salt media formulations especially those used in microbiological applications may require supplementation with additional calcium or magnesium salts (e.g. CaCl2 or MgSO4) or higher concentrations of Phytagel.