Oase BioMaster filter keeps taking in air

[Mel B]

I have an Oase Biomaster 600 on my 300L aquarium which was set up nearly 3 months ago. It had been working well but recently keeps accumulating air And now I have to purge it twice a day by rocking it from side to side. It is frustrating as it reduces the flow. I cannot work out how the air is getting in there. I have checked all the pipe joints and they are tight. Has anyone else had this problem and any advice please.

 

[hypnogogia]

Personally I haven’t, but I have heard of the problem. Is your bio master a new one or second hand? Reason I ask is that apparently Oase changed the design slightly after an issue with the earlier models.

 

[G H Nelson]

Might need a full clean!

 

[Mel B]

The filter was brand new. I did clean it out 2 weeks ago. I will take it apart again tomorrow and give it another clean.

 

[G H Nelson]

Try running some vaseline or silicone grease if you have some, around the seals!