Cal-Boost from Canadian Tire

[fixerupper]

Originally Posted by reefermadness

Even dow flake was like 77%....and its calcium chloride by weight not impurities. Although there will be impurities of different levels depending on the product that is not what you are looking at when you see a percentage like that when it pertains to calcium chloride. You are looking at the amount of calcium chloride.....so it is how much calcium chloride is in the product but most of the rest will be water and a varying amount of impurities.

You're very probably right. To clarify: I wasn't implying they use impurities as measurement standard. I was referring whether they use weight or volume. If a 5 gallon tub is 60% product by volume with zero moisture and the other 40% is something unknown then I'd be nervous about what impurities make up the remaining 40%. If a tub flake product had up to 40% of it's weight accounted for by variable amounts of moisture it may or may not have pulled from the air I wouldn't be quite as concerned. It really doesn't take that much water to add a lot of weigh. As I said, I can't find where they state how they measure. It's this uncertainty that makes the risk not worth while to me. Dow Flake at 77% was probably fairly pure as the unaccounted for balance was also undoubtedly just water. The Dow Flake manufacturer's' recommendation not to use their product in reef tanks could very likely just have been a caution used to mitigate liability. I scoured the forums to find instances of tank issues attributed to using the 77% product but could find none. While the product discussed by the OP might be fine, the 60-100% purity is a deal breaker for me. I screw up my reef setup enough all on my own. I don't need the unclear variables of an untested product helping me 'muddy the water' as it were