I'm still working out my issue of my bottles becoming overcarbed at the 3-4 month mark. I won't have an answer until around March. For my last 3 batches, I've used my immersion chiller. I'm testing my theory that my counterflow chiller is contaminated, and able to survive my soap/bleach siphon through prior to use. I'm thinking about siphoning boiling water through it, prior to using it today. Would that kill any algae, mold, or any other contaminants found inside the 23' coil? Would the exiting water still be hot enough to kill anything on the far end? Has anyone ever done that before? After doing that, I would still siphon soap/bleach through it.