JennM;994433 wrote: I'm not arguing with you
Brian ran a 20L for years, I'm pretty sure he 'only' had a single 240 on it, and a HOB filter.
Try the larger powerhead, let us know what you think. Your original question was would it be OK? Sure. I wouldn't say run out and buy one, but you indicated you have it, so give it a go.
Worst that can happen is that you feel it's more than you need, and you can undo it.
Nothing ventured, nothing gained.
Jenn