My tank, several questions, conversation welcome

[Jeeperscreepersmyth]

Adding co2 this weekend as parts come in and new to that so anything you think I might have missed in my reading would be helpful. Funnily enough I cant grow hornwort but my jungle val and frogbit are prodigious and lead to about a bucket a week being sold and a bucket thrown away. Got some easy green and easy iron on the way so hopefully it will do me better than flourish has been, I am very lightly stocked and have 0 nitrates so could you reccomend a dosage schedule? I tend to run my light at least 12 hours per day because I prefer faster growth and i like the algae at the top of the grass and it's the only algae I ever have much of so I dont mind the side effect. Have a big hob  on the right side and adding a sponge in each back corner, where would you put the diffuser? Ordered a 2" jraldi. Have blue dream shrimp, guppies, and mystery snails, how many bubbles per second should I start with and how hard can I push it for max growth with enough food and light without becoming a problem for my shrimp?  My water goes in the tank around 7.8ph and 300ppm and comes out 7.2 and very soft currently, test kit on the way to give better info on gh and kh. Sorry my thoughts dont flow into nonrunonn sentences. Need help maxing growth without killing my little buddies.

[gardenman]

I'm not a co2 expert, but from what I've read, you'll want the diffuser where you have water flow so the co2 gets evenly dispersed. As to the number of bubbles, that's impossible to say. You'll need a co2 checker to learn the optimal level for your tank. The sponge filters with their airflow will contribute to off gassing the co2 in the water, so keep that in mind. Any turbulence in the water tends to help the co2 escape. When you add co2 to water you get carbonic acid. Acids are low ph, so you'll want to keep an eye on your ph to ensure it doesn't crash. Too much co2 can be very destructive.