# [Wet Thumb Forum]-Eheim Question



## Garmoni (Dec 24, 2003)

Does any one have problems with Eheim canister filters releasing tiny air bubbles? I have two Eheims on my tank. The one on the right side of the tank releases tiny air bubbles. I can see them coming out of the return tube. I notice this more at night and am wondering if the intake is sucking in o2 from the plants. The intake is surrounded by stem plants. I don’t see any air bubbles going into the intake but there are a lot of air bubbles that come out. Could there be a problem with the filter?


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## Garmoni (Dec 24, 2003)

Does any one have problems with Eheim canister filters releasing tiny air bubbles? I have two Eheims on my tank. The one on the right side of the tank releases tiny air bubbles. I can see them coming out of the return tube. I notice this more at night and am wondering if the intake is sucking in o2 from the plants. The intake is surrounded by stem plants. I don’t see any air bubbles going into the intake but there are a lot of air bubbles that come out. Could there be a problem with the filter?


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## Newt (Apr 1, 2004)

Try putting a thin layer of aquarium grade silicone grease around the main gasket - very thin.


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## anonapersona (Mar 11, 2004)

Or Vaseline, which is what Eheim sells for lubricating gaskets.


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## hubbahubbahehe (Mar 29, 2004)

ive heard that vaseline will jack up the o rings...


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## Tarpals (Feb 18, 2004)

VASELINE® PETROLEUM JELLY will corrode rubber and latex. If you want to lubricate your O rings than I would sigest you use a silicone lubricant. In the plumbing section of your local hardware store you will find lubricants made specifically for this use at a fraction of the cost of those found in your LFS.


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## hubbahubbahehe (Mar 29, 2004)

how long does it take before the vaseline corrodes the o ring??? before i realized this, i had been using it for 3 months.


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## Tarpals (Feb 18, 2004)

If you read the label on a jar it says not to use it on rubber or latex. I have herd that it can react with latex quickly enough that you can have the 9-month surprise. Now your rubber O-ring is of a different composition and a lot thicker. I would just keep an eye on it for surface stiffening and cracking.


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## Garmoni (Dec 24, 2003)

Sounds like you are suggesting that I’m not getting a good seal and that air is being drawn into the canister. Thanks for the suggestion. I will try to lube up the o-ring with silicone lubricant and see if that makes a difference.


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## Newt (Apr 1, 2004)

vaseline is a petroleum based product. 

Do you want that in your tank?


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## Garmoni (Dec 24, 2003)

I broke out Eheim manual and found several interesting things documented. It references a ball valve that is accessible when the pump chamber is open. This occasionally needs cleaned and ensures sealing during the suction phase when the filter is started up. I cleaned this ball valve and also lubricated the o-ring with a silicone lubricant. Hooked it all back up and everything seems fine. I will be interested to see if every thing is still fine later tonight when the lights are on. 

The other interesting thing speaks to the debate in this thread over vaseline. The following is a quote right out of my Eheim manual “To ensure proper functioning of the multifunction handle the o-ring must be dampened or lubricated with vaseline. If it becomes more difficult to move the multifunction handle after a while you should renew the o-ring”.


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## galactic_blue (Feb 16, 2004)

Eheim is a German company and their manual probably wasn't written by an engineer. Something could have been lost in translation and the writer may not have been aware of the chemical reaction, just like when you mix bleach and ammonia. If you mess up your o-rings with a compound that degrades rubber and latex you'll just have to buy new o-rings. More money for your LFS and the manufacturer!

Second of all Newt has a point. Fish have eyes and so do you... I've never done it but I don't want that goop in my eyes!


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## Roger Miller (Jun 19, 2004)

O-rings can be made out of a lot of different compounds, many of which are used for their ability to resist chemical attack. I'm not sure that any are actually made out of "rubber." The most common o-ring material is called Buna-N or Nitrile. It is very resistent to petroleum products. Silicone is another common o-ring material and it is not resistent to petroleum products.

I suspect that Eheim's advice is correct.


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## Garmoni (Dec 24, 2003)

This filter is still causing me problems. The maintenance suggested above has not made that much of a difference. I don’t seem to have the problem in the morning but come late evening there is a consistent flow of little bubbles out of the return tube. I’m thinking the intake may be sucking in O2 bubbles from the stem plants that are in front of it. Could this cause the problem or is it more likely the filter is defective? Any other suggestions?


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## JimS (May 3, 2004)

You've probably done this already but have you checked your intake hose. It may have a pinhole or maybe one of the connections between the hose and the filter or intake tube has small air leak.


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## Rumpled (Jun 23, 2003)

Garmoni,
I have two 2026 pro 2 on my planted tank that do the same thing. Don't waste your time any longer. I have replaced all the seals on the units, I have used the silcone lubricant that they supply, I have even done what they say at the web site, of cleaning all the hoses and filters completely. My filters still do the same thing. It is definitely to do with gas exchange. O2 later in the evening is in higher concentrations and this is released into the filter by way of cavitation of the impeller. Eheim seem to think that it is due to a reduced flow of the intake pipe. I did excatly what they said and I still get tiny bubbles. I have found though that reducing the flow rate does help.

Still these filters are the best I have had and if this is the only problem with them, then I am still very happy.

Paul


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## Garmoni (Dec 24, 2003)

Thanks for the information. I figured that one of us had been through the research on this and would have an explanation.


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