Air has CO2. Simply increasing ware air mixing will add CO2 to the tank. My filter spray bar is located just below the water surface and it pointed up and a little sideways. This creases a constant wave at the surface. Or you could create a small water fall. If you have enough mixing CO2 levels will stabilize at 10ppm CO2 with stable oxygen levels..
Many people using CO2 use diffusers and drop checker and aim for 30ppm CO2 level. I tried this approach but it needed frequent monitoring to maintain stable CO2 flow. Too much CO2 and you kill the fish. I switched to
Passive CO2. It is much more efficient then diffusers which release bubbles into the water. WIth diffusers some of the CO2 never dissolves in the water and is simply released into the air. With Passive CO2 all CO2 dissolves in the water. With a diffuser I wasrefillingmay paintball CO2 tank about 3times a year. Since going to passive I have have gone 2 years without a refill in my small shrimp tank. The inverted bottle in the tank should be located at a location with water flow around the opening to get good mixing and to creat a uniform amount of CO2 throughout th tank. I have my passive CO2 system on a timer. it is automatically refilled daily. I adjust by CO2 system so that it usually fills the container without overfilling. If it does overfill the excess harmlessly bubbles out. You don't need a drop checkered my system has goon weeks without any adjustment.
With Passive CO2 and water air mixing at the surface of my tank insures CO2 and Oxygen levels in the water are always stable.
however you also need neutrients in the water for plants to grow. There are 14 nutrients needed and CO2 is just one is missing the plants will not grow or will die. The biggest problem people have with plants is getting the fertilization right. Some fertilizers don't last long in the water while others do. So some people have to dose fertilizer every other day while others only need it once a week. Many fertilizer manufactures assume you have nutrients in your tap water. But in todays world everyone has different water. and if you are using RO water your water has no nutrients leading to deficiency. Having a lot of fish in the tank helps because the fish waste add .nutrients.
I personally am using 100% RO water in my shrimp tank With commercial fertilizers couldn't grow anything but algae. Only after I decided to try making my own fertilizer did I have success with plants.
Due to the fertilizer issues many just try potting soil as the substrate. This can work if you choose the right basin the store but it is impossible to know which product will work best. Others use backyard soilor clay in the substrate. it is a trial and error process. One problem with soil substrates is that they nutrients in the soil will eventually run out. Some people have to replace the substate yearly ore veryoother year. Manyalso refer to old tank syndrome were plants die and algae takes over. This in my experience this is mainly a nutrient issue.
Now a lot of people say some plant only work in tanks thth CO2. No. If the nutrient levels in your water barely enough some plants will grow while others will not. Some people only have luck with one type of plant in a tank while all others fail to grow.
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