Nitrate sol'n; 100,000 ppm. Increases nitrogen, a critical nutrient for survival of photoautotrophs (incl. zooxanthellae), which often becomes biolimiting (slowing or halting primary productivity and cohort growth) in recirculating systems densely-populated with zooxanthellate cnidarians and bivalves, and/or which employ turf scrubber filtration. N deficiency is associated with bleaching. 1 mL per 26.4 gallons (100 L) increases nitrate by 1.0 ppm. 100,000 ppm nitrate, derived from potassium nitrate (anhydrous source, USP).