Suggestions to increase co2 level
I have a 20g heavily planted tank. I inject co2 with 2, 2 liter yeast bottles. Here is my mixture that I use:
2 cups water
2 cups sugar
1 tsp baking soda
1/2 tsp yeast
I also supplement with flourish excel. I started off diffusing with a ladder, but I couldn't seem to get my co2 level up high enough. I now just run the co2 into the intake of my Aquaclear 50 HOB filter. That did help, however for some reason it seems that the highest I can get the co2 level is around 20 ppm, and that's when both bottles are running at peak co2 output (which only lasts a few days, after that they slowly decrease their output). Any suggestions on a diffusion method (or reaction method) that will increase my co2 level more consistently?