Who has used washing soda for buffer?

[Aquattro]

Doug, you may be referring to my recent thread with Randy. The surfactant is added to the VIP brand, according to the manufacturer. Arm&Hammer did not return my email. Randy had made a joke about Canadian soda, not realizing that in fact there is a difference.

Jamie, at this point it looks like a drifting pH probe, rather than a real pH problem. And no, the windows are still open (to my family's dismay) and I have electric heat.