I have a 29 gal lanted tank. I'vebeen using fertilizer for a while, but just this last week got some co2 dissolvable tabs to use. I made a diy system to get the co2 in the aquarium and used it a couple days ago. I also downloaded the co2 calculator for help, but I'm not sure how many times per week I should add co2? The other night (first time i used it), the co2 only made bubbles that lasted a couple minutes. I've had plants in the tank for a while and after a short period, some leaves start turning brown and the plants get really thinned out. I'm sure I have strong enough lighting - about 12 hrs 50/50 6500k. After using the co2 the other night it seems like the plants look a little greener than normal (could just be in my head though). So i'm planning on trying the co2 for a little while, but am not sure how often to add it. Any help would be appreciated.