Current setup is a 15k gallon SWG gunite/plaster pool (built in 08-09) and spa. Current CH level is 170. Kinda confused at all the different numbers/recommendations for CH. Should I bump this up a little, and if so what range should I shoot for 200-250? The previous homeowners left a 5 gallon bucket of Hardness Plus which makes me assume that the pool's CH levels must have stayed on the lower side.