What's A Venturi?

[ellena]

I have this filter but mine was bought second hand and doesn't have the tube bit coming out of the top. Is this the venturi mentioned in the description? What does it do? I'm having problems with this filter, could this be the cause?
Thanks for any tips

 

[Joinerlavin]

I think its like a cap which goes on the filter head and pumps air out with the flow to pump oxygen in the tank. What problems are you having with the filter, The venturi wont be the cause.

 

[chesterscot]

yep that sounds like a venturi basically it sucks in air and mixes it with the water that comes out the filter helping to airate your tank personally i dont likie em but thats my op
hope that helps
scot

just to add it doesnt just suck in oxygen its all atmospheric air it pumps out

 

[ellena]

Thanks guys The problem is it won't cycle basically. I cycled the media in another tank for 7 weeks, then put it in the filter in the tank with a betta. 8 weeks later and ammonia levels are still all over the place.

 

[chesterscot]

your most welcome
the venturi or lack of one i wouldnt of thought would affect your cycle
for eg i ripped mine off lol as i didnt like the fine bubbles drifting round my tank like a snow globe lol with no ill effect
hope that helps some
regards scot

 

[OldMan47]

As others have already said, the lack of a venturi on the discharge of your filter is not affecting the ability of the filter to become cycled.

In general terms, a venturi is a place in a flow path where the pipe gets narrower and then gets wider again. If you connect something to the side at the narrow spot, the higher flow rate in that area creates a slight pressure drop that can suck in whatever is connected to the side. Filter manufacturers use this concept to bring in some air from the tank surface by connecting a piece of tube to the side of a venturi and placing the other end of the tube above the water level. In practice, most filter venturis look like a little piece of plastic that snaps on to the discharge nozzle and is straight with a fan shaped bit right after that. If you needed a diffuser for CO2, you could even connect the CO2 outlet from a DIY CO2 bottle to that same venturi connection and it would help dissolve the CO2 in the water by blowing it around somewhat.