I wrote and now need to correct: > According to my ancient CRC Handbook, a 30% phosphoric acid solution > contains 354.1 grams/liter of phosphoric acid. That also 354.1 mg/l. > Phosphoric acid is 97% phosphate, so the "pH Down" product would provide > 343 mg/l of phosphate. That should be 354.1 mg/ml of phosphoric acid and 343 mg/ml of phosphate. Roger Miller