today's numbers, 17,000 gal rectangular plaster pool. Our municipal water is fairly soft.
CH 200 - I see the recommended range is 250-350 in Pool School. How important is it to keep the CH at the lower end of the range (i.e. do I need to head out to the pool store now to buy calcium adjuster, or is it a sometime-within-the-next-few-days-or-weeks thing?