Vanadium sol'n; 1,000 ppm. Increases vanadium in recirculating seawater systems. Required by photoautotrophs (including zooxanthellae) for photosynthesis; supplementation in V-deficient systems generally increases primary productivity dramatically. 1 drop (0.05 mL) per 6.6 gal. (25.0 L), or 1 mL per 132.1 gal. (500.0 L), once daily to maintain NSW value for S=35. 1,000 ppm vanadium, derived from sodium metavanadate (anhydrous source, USP).