PoolMath says I should replace 100% of my water -- CH (500), CYA (180), Borate (15). However, in So. Cal. we have drought conditions and I would feel somewhat guilty if I replaced the water in my 10,000 gallon pool. What are the consequences of not replacing the water? I keep my chlorine and PH well in balance and I clean the pool frequently, but these other measures have been high for years. I have noticed no physical or health problems. What do you recommend?