Before adding the outside air we were usually reading 7.8 to 7.9 with sort of a lot of soda ash (50ml in a 80 gallon tank, IIRC). But now we are routinely at 8 or a smidge above (8.08, 8.1). So I would say we saw a 0.2 rise in our pH and we use a LOT less soda ash. Ballpark estimate on that is that we use half or less of what we had been using. 25ml is a big dose for us now.Interesting, were you able to measure the difference it caused in ph?
Even with the air pumps pushing air to the skimmer and top of the tank, I can see the impact of using the oven a lot with the windows closed because we will dip back to 7.95. You know, the old logic of "it's cold and wet so let's cook comfort food". So it was a good shift for us and has been sustained even with less soda ash, but it isn't enough to overcome very high CO2. The true test will be this coming winter when we fire up the woodstove and see what happens. We usually crack a window then, so maybe it won't be too bad (no worse than braising a chunk of meat).