I have both a cheap import and a Fluval. The import initially produced finer bubbles but (as with all diffusers) it needs regular cleaning.
Although the Fluval does not create super fine bubbles, at the moment I have it positioned under the HOB
filter intake. So I'm not so sure that bubbles size really matters at this point. Sure, the finer bubbles will dissolve faster, but the larger bubbles will get trapped in the filter media and extend the contact time with the passing water.
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