Citrus are tough and it is doubtful that they will be affected by chlorine in your pool 12 feet away. Keep the plants well fed and do not cultivate within the drip line as the feeder roots are close to the surface. If your garden is liable to be hit by frost, you should consider planting the trees in containers that can be protected or brought inside during inclement weather. For detailed information, contact your local Cooperative Extension office. The number is usually listed in the blue or yellow pages of the telephone directory.