Minecraft 2 farms, creeper farms side by side?

Can anyone help me

I built a creeper farm on the ocean that works great too! But I want more black powder. So my question can I build the same farm next to it again? Or do both not work so well anymore because they take the spawn rate from each other, so to speak?

And if it cuts how many blocks there should be at least because I want to stand there afk and both farms should spawn the chunks load and creepers spawn.

The spawn rate stays the same, you won't get any more black powder.

OK thanks what do you think how far I would have to make the other farm that both work? And if I put myself in the middle of the two farms, would both still work?