[Randy Holmes-Farley]

When DOW states that the new Calcium flake contains 7,000. ppm bromide, does this mean that for every 1,000,000 calcium parts there are seven thousand bromide parts?

No. It is 7,00 ppm bromide and about 280,000 ppm calcium.

And when Instant Ocean states that their product contains 70 ppm bromide..... Does this mean that their product ( the dry salt) contains 70 ppm bromide or that their product after its mixed with water? (at the correct salinity) contains 70 ppm bromide?

I've not seen exactly what they claim, but that is in the final mixed salt water.

4 pounds (1816 g) of Dowflake will contain about 12.7 grams of bromide, if I did the calculation correctly. That will boost 50 gallons by about 70 ppm bromide, or a doubling, if there is no depletion.


so dowflake is ok to use?

It is OK to use as I stated in the first post. It may or may not be OK to use in routine supplementation, depending on how much is used and how fast bromide is depleted (unknown but certainly varies tank to tank).