I cant get it to go below 7.2 even when I have been using DIY C02 for over a week.My kh is 7.0 so should I try to increse my CO2 by adding more yeast.I'm using the 2 cups of sugar with 1/2 tsp of yeast mixture and its connected to a Hagen ladder .Also I have a bio wheel on my penguin filter .Can the bio wheel be causing to much surface disturbance and keeping my CO2 from reaching is peak.I see that alot of people remove the wheel from the filter.Also,about the C02,how many bubbles per second should I be getting out of the end of the tube that goes to the ladder because I get one bubble about evry 5 to 6 seconds.