I'm currently injecting chlorine into my well water supply to help with sulpher. It has proven to be very helrpful in making the water a better quality. The down side is the fact chlorine is hard on the bladder in my pressure tank.
I replaced the tank approximatly one year after adding the chlorine, and moved the injection site to after, and above the bladder tank. One year later it failed again!
Do I need to put a "U" in the pipe after the bladder tank, to keep the chlorine from migrating back to the tank? The present configuration has the injection site 1.5 feet above the bladder tank, and a total of 2 feet away. I need to replace the tank right away, but would like to get more life out of it. Just need some professional advice. Thanks in advance.

This may have some info that you can use.

http://www.scgov.net/EnvironmentalServices/Water/Utilities/DrinkingWater/documents/WaterSystem_disinfection_Flyer2.pdf

This article says it's OK to run bleach through your system.
The simplest and most effective product for disinfecting all parts of your water system is plain chlorine bleach with no additives. Whenever the pump is primed, chlorinated water should be used. With proper precautions, chlorine solutions are safe and easy to use. After disinfection, the chlorinated water should be flushed from your well and plumbing system. The chlorinated water should not be discharged directly into your septic system. An outside faucet and hose should be used to discharge the chlorine solution to a location away from lawns and gardens. Good luck, Tom

If you want to prevent backflow, you can install a checkvalve between the injection point and the tank.