Micro bubbles from skimmer


New member
Does anyone else get a constant stream of micro bubbles from the vent in their Tunze Comline skimmer?

Whilst the bubbles don't make their way into the main tank, which would be most annoying if they did, I was wondering if the fact that it happend at all was a good sign or not?

If not is there anything I can do about it? I've not noticed any difference in the bubbles as I adjust the air screw.

Thanks in advance for any help / comments

This is a normal condition when the skimmer is new or completely cleaned. The pump at peak performance will cause some microbubbles to exit and this will subside within 2 weeks. This is mentioned in the manual. Barring this the other causes are gas saturation issues. If the aquarium has excessive carbonate hardness and thus high CO2 retaining properties the effect is similar to the pearling seen on freshwater planted aquariums with CO2, only so much gas can be dissolved in the water and the oxygen saturated water near the skimmer must degas. Similarly during peak photosynthesis in aquariums Oxygen saturation can have a similar effect. Lowering KH or increasing circulation can help with these issues. The only other possibility is a very high flow through the sump, more than 5 times tank volume could cause excessive turbulence within the skimmer allowing bubbles to exit.