You need to turn it down, are you using a bubble counter?
I'd get a CO2 drop checker if I was you, some 4dKH standard for it, then you can dial in to a nice green color and know your levels are right.
My rule of thumb, turn it up till the fish act weird, crank it back down till they're normal and leave it.
Don't worry about pearling too much, it has a lot to do with light, maybe other nutrients too. That's if the plants are happy, if you simply turn up any gas in the tank it'll become supersaturated and bubbles will form. You see that a lot with water changes using tapwater that isn't gassed out.
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