I'm not sure if that is any good. I use ExoTerra Calcium w/D & I haven't experienced any problems so far. I got if off Amazon.com & it was relatively cheap and, as long as it doesn't outlast its shelf-life, it should last a long-long time. Here's a link... not quite the answer to your question but I hope I helped a little bit.
Personally I'm not a big fan of the spray. I use it in the powdered form, mixed in with their "mush" (vegetables + mazuri mixed together in a food processor, fed twice weekly). That's the only meal they get the calcium with.
When we look for a calcium supplement, the PERFECT version would use a very, very fine-grained calcium that delivered a good dose of calcium in the volume.
Calcium citrate is probably the best calcium supplement as far as being fine-grained and very easy to absorb, but it only delivers a weak dose in a given volume of the powder or spray so you need to use more to accomplish the goal.
Calcium carbonate powder, the most common version, is a bigger grain but delivers more of a punch, so it is the most often used.
The spray is going to be even more dilute, and cost more per dose than the above. However, if it delivers a finer powder (based on what is left after evaporation), then it might be worth the cost. Better yet- if it covers the bitter taste of most calcium powders it would be a bonus!
Cuttlebone is great- crunchy, lots of torts love it, etc., but as a primary calcium supplement, it is not as effective as a fine powder would be. The large chunks do not dissolve completely or quickly. However, it does help.