Ahhh petunias, my other favorite annual, 
I had the same tea bubbling for years, 2 liter bottle with an air pump. I call it a perpetual tea, I have a microscope on hand to look at the microlife. I personally like brewing tea this way, the microlife develops over time, you have a more complex micro heard over time, I would add typical commercial inoculants, and soil from the park that was under leaf litter.
The only thing that didn’t last in the tea that had kelp in it was fungal hyphae, they were short lived but could be flipped to a fungal tea with the addition of carbohydrates like oats or rice, and hit with a commercial myco inoculant.
It takes a bit to learn how to manipulate the tea, but its fairly easy, add your feed like kelp, then do a wet mount for your microscope to see what the tea is doing.
So the typical tea that had kelp in it had lots of microbes and amoebae, perfect for most annuals, another positive benefit of the longer brewing teas is glomalin, or its assumed the sticky viscous nature of the straight tea contains glomalin, a key component of soil tilth.