Zinc sol'n; 1,000 ppm. Increases zinc in recirculating seawater systems. Increases primary productivity. Required by photoautotrophs (including zooxanthellae) for photosynthesis, pigment production, DNA transcription, CO2 fixation, phosphorus acquisition. 1 drop (0.05 mL) per 33.7 gal. (127.4 L), or 1 mL per 673.1 gal. (2,547.8 L), once daily to maintain NSW value for S=35. 1,000 ppm zinc, derived from zinc chloride and/or zinc sulfate (hydrated source, USP).