Tunze 9012 micro bubbles from the bottom

[The Opinionated Reefer]

I have the tunze 9012 in tank skimmer which is highly rated but no matter what I do it spews microbubbles from the bottom even when the skimmer if fully open. Also, I have to have the air intake turned down a lot or it overflows. I have the water line about halfway up the intake of the skimmer and can't really move the skimmer any higher due to a rim around my tank. I noticed if I have air valve fully open the skimmer makes a noise like its running dry now and again but this does not happen when the air intake is closed. This is the original version of the skimmer that I got second hand. I have had it apart and cleaned everything but it does not help.

Here is a short video of the issues:



Any suggestions?

In the video the air intake is about half closed and it is still almost overflowing. I ran the skimmer for about a month with the air intake screwed almost closed and it skimmed well producing black smelly skim-mate but the bubbles persisted. The video was taken after i recently cleaned it.

I also read in the manual that it can be converted into a contact skimmer and this should reduce the bubbles at the outlet. But what does this actually mean? What's the difference between a contact skimmer and normal skimmer? How will this affect the performance of the skimmer etc..

 

[rvitko]

I think the main issue is the depth. You are at or a little past the maximum submersion depth and ideally we would adjust depth first and then work with air and close the air only as little as needed. You can space the skimmer forward by an additional set of magnets sandwiched between the inside set and the glass but this is not an inexpensive solution. I run mine with around 1/4 of the intake submerged. The more you close off the air, the faster the water flow is, so the more bubbles escape (less air equals more water). They also tend to eject more bubbles for a couple weeks when new.

A contact skimmer means the water just recirculates inside, this is desirable because plankton will not be actively removed, but, it also skims much slower, waste diffuses in and is not actively pulled in. Our oldest skimmers worked this way, they worked well, but the response time to waste was much slower than one actively pulling water from the surface of the tank.

 

[The Opinionated Reefer]

Would turning it into a contact skimmer reduce the overall performance of the skimmer? I'm not to bothered about the surface skimming capabilities and I have a separate surface skimmer that keeps the film from building up and pumps it back into the water column.

 

[The Opinionated Reefer]

I managed to raise it but the skimmer became much more noisy and the bubbles from the bottom were still there. There must be something else wrong with it. It's an old skimmer.

 

[rvitko]

What do you mean by it is old? Have you owned it the whole time or did you buy it used? In general after 6 months the pump should be broken down and cleaned. it could be something is jammed with the impeller or air intake.

In recirculation it would be a less powerful, less responsive skimmer.

 

[The Opinionated Reefer]

I got it used. I dismantled the whole thing and cleaned it last week in an attempt to fix the bubble issue.

 

[rvitko]

I might double check that everything is in correctly, Any additional photos of the pump, internals, etc would help.

 

[The Opinionated Reefer]

Stripped it down and checked everything. All seems fine. I made the contact skimmer modification and it has reduced the bubbles considerably. I can now have the air valve almost fully open. I do see what you mean, it does seem less powerful.

How do you know when it needs a new impeller?

 

[rvitko]

Everything looks correct, typically a bad impeller will have seperated so the magnet and needle wheel are not attached, you can pull them apart or the impeller can spin without the needle wheel. Everything looks good and correctly assembled. Is the impeller cover installed so it is symetrical, it can go on two ways, one way is wrong and it will be asymmetrical, the solid plate should face the wall so it blows the bubbles out to the back and sides.

 

[Superlightman]

Hello I have the same issue with the bubbleS and mine is new,many people over the internet seems to have the same problem but not solution? Someone could fix it without changing it in a contact skimmer? To make it a contact skimmer is it detrimental for tridacna clams..?

 

[The Opinionated Reefer]

I never found a solution and sold it on

 

[Superlightman]

**** wIhope I would find,because they are not so much choice on good internal skimmer,it do a very good job,but the bubbles are killing the view in the aquarium.What do you buy

 

[The Opinionated Reefer]

I got a tank with a sump

 

[Superlightman]

Well that is not possibel for me actually...

 

[rvitko]

Bubble issues will typically come from the depth of submersion and closing the air too much. Never submerge more than half of the intake grating, work with depth first and close the air as little as possible. As you close the air, water flow increases, this means the bubbles are moving faster and further, so more are ejected. Generally the sweet spot is that about 1/4-1/3 of the intake is submerged and the air is closed less than 1/3rd of the way. If these are set correctly, typically the bubbles will be greatly reduced after the skimmer breaks in, usually after 1-2 weeks of use.

 

[Superlightman]

I tried different depth unfortunately it change nothing.the air is fully open has this new skimmer not come with the possibility of change the air input (maybe something is lacking in the box?) , i can just change the power of the pump.

 

[rvitko]

Is this a DC 9012? On the DC model the pump speed generally is down toward the minimum setting. It is near impossible to run with a pump speed over 50%.

 

[Superlightman]

Is this a DC 9012? On the DC model the pump speed generally is down toward the minimum setting. It is near impossible to run with a pump speed over 50%.

Yes it is a dc 9012,the speed is at minimum or else it is too strong and goes full in a minut

 

[rvitko]

That would be correct, usually 20-40%. Is it possible that the plug is missing from the bottom or the pump, or from the back of the skimmer? Parts 9012.110 or 3130.480?

 

[Superlightman]

That would be correct, usually 20-40%. Is it possible that the plug is missing from the bottom or the pump, or from the back of the skimmer? Parts 9012.110 or 3130.480?

Mmm ,this i don't know,hope not as she is new,but i will have to check this when Icome home this week