Some people are successful with that method, although the water changes do get expensive after a while, particularly if you don't get much rain as makeup water. Also, once you do a partial drain/refil, you have to re-balance the water again, which takes more chemicals (more $$) and is a pain to do. Not to mention, near zero cya will offer very little protection from the sun, so you'll be using considerably more Cl to keep your pool in the 1-2 ppm range.

Michael