Problem With Fluval Filter

[poohbear1]

hello,
After a few months of an empty tank I cleaned it all out and set it up again.
My problem is my fluval filter isn't blowing out air bubbles. Its taking in water and blowing out water but no air bubbles, when I open the air pipe at the top there is water coming out of it.
Can anyone help as its annoying me.
Thanks

 

[Davo86]

hello,
After a few months of an empty tank I cleaned it all out and set it up again.
My problem is my fluval filter isn't blowing out air bubbles. Its taking in water and blowing out water but no air bubbles, when I open the air pipe at the top there is water coming out of it.
Can anyone help as its annoying me.
Thanks

can't really help with that but if you position the filter so that it produces surface movement that will produce a lot more oxygen,

 

[Matty P]

You don't have to make your filter make air bubbles it is just a preference, as long as the surface is well agitated and the water parameters are correct then your fish will be absolutely fine and have plenty of oxygen. Is the pipe at the top well above the surface?

 

[poohbear1]

Yep the pipe is well above the water and the water is agitated.
Its annoying cause I bought a spray bar for when I set this tank up again.
thanks for the help

 

[poohbear1]

ok I took filter to bits yet again and put it back in tank. I now get air bubbles in spats but when I put the spray bar on I dont get bubbles and water comes out the air intake tube

 

[rabbut]

The problem lies with pressure. Water being pushed out of the outlet means that there ls low pressure arround the venturi tube where it joins the outlet. Placing the spray bar mon the outlet means that there is positive pressure at the base of the tube, hence water is pushed up the venturi, and out the top, rather than dragging air down. The pressure can only pull the air down a cirtain depth. Below that depth, there is not enough pressure to cotinue putting air down. IMO the best way to airate the water would be to fit the spray bar, and point it at the surface. I you want to keep running the venturi, remove the spray bar, and move the filter closer to the surface.

HTH
Rabbut