Spectrum CA138

[REEFKEEPA]

I got some anhydrous Cacl2 from my pharmacist friend and would like to know which product selection I should use in the calculator that is provided on the site.
I looked at the dow flake but it says I would have to add more than Sea Chem RA Ca is this right????:confused:

[bertoni]

In the traditional version, there's a line for anhydrous CaCl₂ (PelaDow) which should be fine.