The Puffer Forum

I have experienced something very strange. In several of my cory tanks, I have an Eheim Pro 2224 external filter. Because of the food I feed my cories, the filters needs rinsing quite often (for an external filter, that is). Much more often than in other tanks with the same kind of filter, but other kinds of fish. After some time with using those filters, I put a diffusor on the outlet on some of the filters. After that, I haven't had to rinse any of them. The last filter I put a diffusor on, I had to rinse very, very often. But now I haven't rinsed it a single time after I put a diffusor on the outlet! It's really, really strange! I am very curious how this will be during summer. Can anyone please explain for me how this is possible? I have some theories on what can have an effect, but I can't see why it would have that special effect. Why don't I have to rinse my filters after I put on a diffusor on the outlet?

My guess would be if restricts the outflow or divides it into two directions it altered the preexisting current in the tank. Maybe b4 it was enough flow to suck food up before its eaten and now the new current gives food time to settle/be eaten...

Mind Bottling...you know when all you thoughts get trapped in your head , like a bubble...

Is this a water flow diffuser or a CO2 diffuser?

It is a diffusor to mix air into the water when it flows through the outlet. To be exact, it's this thing.

SammyDee wrote:Maybe b4 it was enough flow to suck food up before its eaten and now the new current gives food time to settle/be eaten...

No, it couldn't, as I've covered the intake with a piece of sponge, to prevent any fry from going into the filter (they do anyway, but only a very few of them). But I have a theory that the diffusor increases the pressure inside the filter, and that this is what's doing the difference. But I don't see why the increased pressure would give such results. I really don't get this, as the difference between before and after the diffusor is big.

could the diffuser actually be allowing debris to settle as opposed to being turned up?

I'm a little worried. Sounds like its not getting in to the filter/ or its not staying in the filter. The whole point is to remove it from the water column. A few more cleaning's is much better than rotting organics in the tank.

Rusty wrote:I'm a little worried. Sounds like its not getting in to the filter/ or its not staying in the filter. The whole point is to remove it from the water column. A few more cleaning's is much better than rotting organics in the tank.

There's not any more debris in the water - not visible at least. And it's not talking about a few more cleanings - the change is huge. From at least once a month (one even more often), to once or twice a year. There's also a change in how much mud is getting stuck in the hoses. In the filter where I had to rinse the most often, I also had to rinse the hoses at the same time. Now I can leave them too.
My second theory is that the increased amount of oxygen in the water can have some effect. I really don't know why though. I just find it all very, very strange.

And, I forgot: it gives more waterflow too, as the water now comes out of a single hole, and not many, as it was before.

Maybe the single outlet allows water to pass more easily through the entire filter. Just thinking this if you are getting more flow with a diffuser. Interesting. Might only be a fish tank filter but fluid flow can be quite complex.

More flow would mean more oxygen in a given time for the bacteria, too - I had heard that the bacteria inside an external can use up most of the exisitng oxygen in the water which is why another form of aeration is reccomended even if it's just putting the external filter return at the surface to re-oxygenate it. If there's more bacteria, they can process any sludge build up more quickly. Mind you I think a lot of the grey jelly like stuff in filter sponges is the bacteria.

Basicly, just what you said