CYA level is measured in parts per milion (PPM). That means that the size of the pool is irrelevant. Your local weather conditions and how your water retains chlorine will determine the ideal. As a WAG, in the NE, 30-50 is a good level. In the deep South a higher level of 50 to 70 is preferable.

But you MUST retain the correct residual levels of chlorine for your level of CYA.