I'm in the process of getting a 2000 gal swim spa . The salesman is giving me "Natural Spa Minerals" to add at a level of 160 lb in 2000 gal. If this is all MgSO4.7H2O that would be something like 4700 ppm (somebody please check my math). Obviously way over the recommended TDS. Should I reduce the level or just skip it all together?