Ive done alot of research but let me explain my set up for you. I have a 6 gal tank that is approx 12 inch tall. It is a fertilized and currently has a DIY co2 on it, i did this by taking a 2 liter bottle and adding sugar and yeast, it is connected to a special co2 bubble (whatever they are called). The tank also has high lighting and is completely planted carpeted and bigger plants. Im about to be adding in my cherry shrimp and know that gassing them with co2 is possible at night. And im wanting to avoid this of course. Yet i dont want to spend alot of money upgrading my co2 system. The co2 bubblier is only 8-9 inchs from the water line. The majority of the bubbles reach the surface meaning not all the co2 is dissolving or there are other gasses present. Im wondering if I can get away with this co2 delivery system. Or what simple upgrades could be made so that it doesn't run at night? from what i understand it would be at night i would gas the shrimp? Also I do a 50% water change 1 if not 2 times a week.
Options ive thought of-
1. Instead of a 2 liter bottle maybe like a 12 oz bottle, scale back the yeast and sugar so there is less co2 being produced
2. Releasing the pressure in the DIY bubblier before bed. so it would take maybe 4-6 hour for the pressure to build up again and start bubbling
3. Upgrading system (Dont want to do this really, but i though of it)