Werleman

Good Day All, I have a hot tub for 3 weeks now and refilled it twice because i keep getting below when it is not in use after the first or second usage. I regulate my water. My hardness is down however where i am they we have 4 stores where they sell pool/spa supplies and they do not sell calcium. They all tell me that Its not really a big deal. I use bromine tablets Also when i turn it on it creates some bubbles. I will attach that picture in a seperate post. I just shocked it and still its like this. I do not know what to do. Any assistance is appreciated. Thank you guys :). Jonathan