Who has used washing soda for buffer?

[Aquattro]

Victor, I went thru all that with Randy today. My alk is bouncing between 2.5 and 3.5 mEq/L. I no longer use vinegar in my saturated kalk, dosing 5g every 2 days. My reactor was turned off last week. pH still can hit 7.6 at night. I'm building a much larger reactor that should be done this week-end, hopefully that helps. I still can't figure why the low pH though