Only a lesser extent, this is kinda like veterinary medicine vs human medicine. You can buy the same drug for your dog for 20% of the cost for yourself. However, would you take your dog's medicine? Both are the same, however, regulated differently. In the case of reef additives, (which although aren't regulated to the best of my knowledge), care is taken to test to make sure they are safe.
These guys claim their material is 100% calcium chloride.
http://secure.poolcenter.com/prodinfo.asp?number=NY595
However, with that being said, I am not sure they are held to the same reporting guidelines given the application. Therefore, I am not sure 100% isn't the same as 99.5%. This is something the chemistry forum might be able to comment on. Either way, I am sure there is nothing in there outright harmful as it is for human contact. However, there is supposedly nothing harmful in tap water, yet most don't use straight tap water in their tank either.
I don't mean to sound condescending. However, typical pitfalls most FW enthusiasts make when switching to a reef is to underestimate the delicate nature of reef water chemistry. Marine inverts such as corals are 100x less forgiving than the most delicate FW fish.
Personally, I would run whatever product you find by the guys in the chemistry forum. There are a lot of practicing chemists in there that can steer you in the right direction.