My Spa does run over into the pool. I also have some sheer decents that I run once in awhile. I suppose that qualifies as airation. Assuming that I will be continueing to use these features, will I be dealing with low total alkalinity issues? I have a SWC that will go online in a couple months after the pebbletech finish cures. I am expecting that I will have to add muriatic acid regularly, about once a week, to keep the Ph balanced. That seems to be the standard expectation when running SWC units from what I've gathered. If this results in low TA issues, could regular addtions of baking soda also be in my future? As for Calcium Hardness I do not yet have this test, should have it soon.