Aqua One 620T Filter Unit Question

[Humanist]

The Aqua One 620T aquarium filter unit in the hood has several holes which are not explained in the instructions. One of these is at the back of the right hand side. It is behind the filter outlet hole. Much of the water returning to the tank runs out through this hole, which causes a constant trickling noise. If all the water ran through the filter outlet, there would be less noise since water returning this way enters the tank under the water surface. Does anyone know what the actual purpose of this extra hole is?

 

[KittyKat]

Photo? Did you buy the tanks second hand? As far as I know, there should be only the one hole for the outlet there.

 

[Humanist]

Photo? Did you buy the tanks second hand? As far as I know, there should be only the one hole for the outlet there.

The tank was bought second hand, but the filter unit has not been modified in any way.

Apologies for the picture quality. It's a bit difficult to see because of the water movement and because I only have a mobile phone to take the pic.

It's just the upper compartment that I'm talking about, ignore the lower one. There are two holes in the upper compartment. The lower hole has a plastic elbow attached underneath, which returns the water under the surface and creates the current. The upper hole is just a plain hole and much of the water falls straight into it from the filter, creating the noise. The upper hole is larger, so the plastic elbow will only fit on the lower hole.

 

[hillbilly]

I've always assumed it's there so that if the angled filter outlet got blocked the filter wouldn't overflow.

 

[Humanist]

I've always assumed it's there so that if the angled filter outlet got blocked the filter wouldn't overflow.

Yes. You'd think that it would be elevated a little though, so that the water only goes through it in the event of a blockage.

 

[KittyKat]

I can't make much out from that photo.. but here is how mine looks look like (I have personally seen these in the AquaStyle range and AquaStart range, and they do all look the same):

The top, round hole is the outlet, it is the bit which has the "arm". The bottom, large, hole is the overflow.

And you are saying that the top section has two holes in it?

 

[Humanist]

And you are saying that the top section has two holes in it?

Yes. The offending hole is actually elevated a couple of cm, but that doesn't help because the filtered water pours straight into it. Managed to take a better photo by switching the filter off...

 

[KittyKat]

The "arm" can be moved up and down (with difficulty), if the top of yours is above the lip of the plastic around it, try lowering it.. otherwise, I would probably stuff some filter wool into the other hole, to see if that gives the water a preference to go down the right one (if you do this, watch to make sure it doesn't flood the house!).

 

[Ashers]

Mine was the same, they all are! Just put some coarse filter foam in the hole to stop the venturi effect, worked for me! Used coarse foam because it doesnt block as easily as the fine foam.

 

[doresy]

Looking at your second picture I reckon there should be a short length of standing pipe attached to the lip of the other hole to act as an overflow if the outlet hole got blocked and the water level rose.