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RogerI agree. Â There is no need to raise calcium hardness in a spa. Â I never added calcium until recently. Â My dealer also agrees there is no need. Â I now raise it only to 100 to give my water a little more polish. Â Don't even know if it really does that.
So why is it that dealers/etc are so quick to strongly advise against filling a tub with softened water? Is it the sodium, or other ions used to soften the water, or is it  the lack of minerals other than Ca that are a problem?Funny that we have two nearly identicel threads going  now........
I am not a chemist, so forgive me if what I say is not totally exact.2 reasons for calcium hardness:1. Â Soft water foams. Â Often foaming issues are really soft water issues, not from lotions, soaps, etc.2. Â You Taylor Test Kit fans should know this one (unless they have changed their instructions and support documents). Â Water balance is the relationship of at least 4 factors, temperature, pH, TA and Calcium Hardness. Â If your hardness is low, then, according to the Langlier (sp?) index the industry uses, your pH and TA have to be adjusted accordingly. Â pH bounce could be the result, as you would think your TA is in range, but it really isn't.Does this begin to answer the question?