Converting the high-flow bubble rate to the normal-flow bubble rate can be done by doing the following:
1) Measure the rate in normal-flow mode. (A bubbles per second)
2) At the same CO2 rate, measure the rate in high-flow mode: (B bubbles per second)
3) Divide A by B

1) In the normal-flow mode, the rate is 2 bubbles per second = A
2) In the high-flow mode, the rate is 1 bubble every 2 seconds (or 0.5 bubbles per second = B)
3) A/B = 2/0.5 = 4 So 1 bubble in the high-flow mode = 4 bubbles in the normal flow mode.

Therefore, if you count 2 bubbles per second in the high-flow mode, the normal-flow bubble rate is 4×2 = 8 bubbles per second.