I have one c02 ladder diffuser in my 55 gallon tank thats powered by 2 2 liter bottles of 2 tsp yeast, 2 cups sugar, 1 tsp baking soda, and the rest water. I tend to get between 5-6 bubbles produced per second in my aquarium and I was wondering if I should get a second diffuser or if one is good enough. The bubbles do seem to shrink by 1/2 by the time they get to the top. After a day of running it my ph dropped from 7.8 to 6.2. I'm thinking of disconnecting my power filter on top and just using a canister filter. I was wondering if it would be a good idea to have a bubbler timmer set up so that it goes off at night to give the fish more air in case they run out of 02 at night. Do you think the fish need added oxygen at night and if I went with the bubbler would my fish get ph shock if it took most of the c02 out of the water and raised the ph.