I have a 20 gallon high with a kleiner bar sword and amazon sword. It is stocked with 2 lyretail mollies, 1 platy, and 4 zebra danios and 1 amano shrimp. Parameters are 0 ammonia and nitrite, around 20 nitrate. The lighting is low .75 wpg but I am upgrading soon to 2 wpg. If I don't have an air stone and zero surface agitation, will the fish produce enough c02 for the plants to use?