Air Pump and diffuser setup question

I got a 120 Litre/minute airpump and im looking to power 12x airstones or diffusers. I noticed though there is 4mm and 8mm tubing size diffusers. Would I be better off going for a 12x 8mm manifold or a 12x 4mm manifold (bearing in mind if I use the 12x 8mm manifold I wont have to use a reducer to reduce the pump outlet from 25mm to 20mm, because the 12x 4mm manifolds use 20mm tubing but my pump outlet is 25mm)? Will there be much of a difference in flow? Would it be able to handle 12x 8mm airstones or diffusers?

Go with the 8mm. Reducing increases velocity but reduces pressure.

redi jedi said:

Go with the 8mm. Reducing increases velocity but reduces pressure.

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Thanks for the reply, so I would be essentually supplying the roots with more oxygen with the 8mm?

More pressure gives you smaller more energetic bubbles. The bubbles breaking at the surface is where the majority of gas exchange takes place. You want it to fizz like soda pop, that's beauty.

redi jedi said:

More pressure gives you smaller more energetic bubbles. The bubbles breaking at the surface is where the majority of gas exchange takes place. You want it to fizz like soda pop, that's beauty.

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Ah I get it now thanks. So as little restriction as possible is best.