Andrey Tarasevich wrote:

I notice that instead of going all the way up CO2 bubbles are collecting in my
new Hagen Nutrafin diffuser forming larger bubbles that just sit there all the
time. I tried forcing them out of there but eventually they reappear. Meanwhile,
I saw a working setup in my LFS and it didn't have any bubbles stuck in it. I
also read somewhere on Google that this is normal for freshly installed
diffusers and eventually this issue will go away. Did anyone experience this
problem with their Nutrafin diffusers? Will the diffuser eventually clear up?
And if it will, what's the physics of this process? I.e. what exactly is going
to change so that the diffuser will no longer trap and hold CO2 bubbles?

Happened to me as well when I first installed my diffuser. After a few
days the bubbles started to travel the entire path.

I'd expect it's caused by some manufacturing residue, perhaps a mold
release compound used when the diffuser was made. You might try giving
it a thorough cleaning with hot water and a tooth brush, but that's
probably overkill.

Of course, you will have to clean the diffuser from time to time
anyway, as it will tend to collect a lot of debris. About once a week
I use a toothbrush on mine, followed by blasts from a turkey baster to
get the far side of it cleaned up. This keeps me from having to pull
the whole thing out (which is a lot more trouble than I generally want
to go through).

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