calcium and alkilinity test kits

[benni]

Ok here we go again I have a 28 gal. bow front that i am making a reef tank out of. I have it set up and I am almost at the end of my cycle. I was read that with all the coral I will need to be adding liquid calcium to my tank there were alot of warnings to keep this value between 400 to 450 ppm. thats all well and good but when i went into my local petco i couldn't find a test kit for calcium or alkilinity. So I talked to my mom and she said that she has to test her hot tub for calcium. Is this the same kind of test or does it read a diffrent chemical? and if it isn't whats the best place to get the test kits??