Microbubbles Tunze 9002

[jamierk]

Hey guys

I know this is a fairly common thread, but i've searched and read as much as possible and havn't found an answer yet. I have a tunze 9002 installed on an intank media rack in a RSM130D. I've had microbubbles issues with it, so i pulled it out and put it in display so i can watch where they come from. They seem to originate from the very bottom slot on the skimmer (underneath), and interestingly enough, continue despite me shutting off the air entirely to the venturi. I've double checked all the connections and there is definitely no bubbling in the internal water so i don't know where this would be coming from. I've tried running the pump by itself (not inside the case) with no air line attached and i can't see the microbubbles forming anywhere, so i can only guess that there is cavitation happening. I've cleaned the impeller and no change. Any thoughts?

Thanks

Jamie

 

[jamierk]

I stand corrected, they go away after leaving the air supply off for a couple of hours, but start instantly when you open the valve at all. Is it normal to see large ammounts of bubbles emerging from the bottom slit?

 

[rvitko]

Bubbles can have several causes.

1) Mechanical, this would be limited to a brand new skimmer which has not fully broken in or one that is assembled so the airline is looped in front of the outlet nozzle so bubbles are bouncing off and not traveling the full distance. Fixing the airline position or giving it a couple weeks would solve this.

2) Gas saturation, if the water is new and has a lot of dissolved oxygen, the supersaturation will be degassed at any point where there is a pressure change, in time this will work itself out. In the case of oxygen, it will generally get worse the longer the lights are on since photosynthesizing algae and corals will add to the oxygen load. CO2 saturation is also possible when the KH excedes 14 dKH.

3) Surfactants, many additives and filter medias will change the waters surface tension, essentially making it more slippery so the bubbles can travel farther. Stress coat, dechlor, vitamins, new unrinsed filter floss, can all be potential surfactants that can cause this, eventually these compounds decompose and/or are removed so long as more are not added.

 

[jamierk]

Thanks Roger, I will give it a week or two to see if this reduces at all.

Cheers

Jamie

 

[The Computer Ox]

Thanks Roger, I will give it a week or two to see if this reduces at all.

Cheers

Jamie

Jamie,

Are you still having the same issue with micro bubbles?

 

[TA]

Rather than starting a new thread, I thought I'd just add on here.

I am also having similar issues as jamierk.

Tunze 9002 in second chamber of Oceanic Biocube 29.
Been running 6 weeks now with no change (I'm past the broke in period).
Waiting is over...won't make a difference.
It's not a problem with cavitation or pump needs cleaning.
It's not airline tube in the way.

I'm NOT interested in 'cause' of micro bubbles....that's been beaten to death on the internet.

I want to know WHAT I CAN DO to eliminate/reduce the bubbles.

Specifically,WHAT KIND OF SKIMMER MOD/BLOCKING SLITS/WATER ENTRY-EXIT PORTS etc...I CAN DO that will PREVENT THEIR ESCAPE FROM THE SKIMMER without effecting its function.

moving the skimmer not an option

this is purely a "skimmer-mod-to-block-micobub-exit" post.

 

[rvitko]

The only idea that comes to mind is a body that is effectively 1" wider and deeper, a tube the skimmer would rest inside with 1/2" on all sides. It would need to have slits or openings for intake and output.