If your ph is 8.2 in the morning, you can safely add some baking soda; it won't drop your ph that dramatically. You don't say how big your tank is, but try adding maybe a teaspoon or so dissolved in R.O. water for every 50 gallons of tank volume; you can do that each day until your dkh gets up into the 9-10 range, then let it go for a while and see what happens.