I am in Australia and have a in ground concrete Q-Quartz pool (www.qquartz.com.au). The manufacturer recommends that a product called Cal-Stop is added to the pool every six months http://www.quartzon.com.au/calstop.php . The ingredient is Active Polymer Complex and it costs ~$72 for 5 litres (1.3 gallon) from my pool store. Is this necessary or is it just a good money maker for them?
I have also just come across Borates on this website and see that is is $75 for 20 pounds at the pool store (on special down from $115) - with my pool, it looks like I will need ~$150 worth - what would you expect to pay for 40 pounds in the US?
My water is 6 degrees C today or 43 Fahrenheit so a few more months before it warms up enough to swim in October or November, the kids get in around 70F, I wait until at least 80F.