# Eheim 2215 or 2217 for 55G Tanganyika



## Ensorcelled (Mar 1, 2011)

Just as my title post says, I'm trying to decide on a single 2215 or 2217 for my 55g lake tang setup. Stocking list is as follows;

6 Julidochromis Ornatus
6 Multies
8 Congo black Calvus

I currently run a fluval 406 but I'm honestly ready for something simpler and the classics have always been something I have wanted to try. I feel that the classic would provide me with better filtration overall considering the fluval has noticeable bypass, which bothers me a little more than it probably should. Anyway, so should I go with a 2215 or the 2217? I have seen a 2217 in action on a 55g in the past and it seemed to have quite a bit of current which I'm not sure my little ones would like too much, but I also don't want to just barely cut it with the 2215.


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## fmueller (Jan 11, 2004)

How much current these filters produce depends largely on the way you set up the outlet. The only reason not to buy a 2217 would be the higher price. If you can swing it, you will not regret the 2217. That said, a 2215 can also filter a 55G very capably. My first tank back in Germany was a 200 liter - about 50G - and I ran it with a 2213 for many years. Of course when I upgraded to a 2217 the difference was like night and day. The main advantage being a better flow through the entire system and less need for filter maintenance. Here in Ohio I started my fish-keeping career with a 2217 on a 29G - overkill, but fun! I now run that same 2217 on a 75G, and honestly I have never seen a need for more filtration on that tank.


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## Ensorcelled (Mar 1, 2011)

fmueller said:


> How much current these filters produce depends largely on the way you set up the outlet. The only reason not to buy a 2217 would be the higher price. If you can swing it, you will not regret the 2217. That said, a 2215 can also filter a 55G very capably. My first tank back in Germany was a 200 liter - about 50G - and I ran it with a 2213 for many years. Of course when I upgraded to a 2217 the difference was like night and day. The main advantage being a better flow through the entire system and less need for filter maintenance. Here in Ohio I started my fish-keeping career with a 2217 on a 29G - overkill, but fun! I now run that same 2217 on a 75G, and honestly I have never seen a need for more filtration on that tank.


Thanks for the fast reply fmueller! I am pretty much leaning toward the 2217. My initial plan was to run the intake on the left corner side of the tank and the output spraybar on either the other end "spraying" toward the end with the intake instead of having it on the back wall spraying towards the front of the glass.


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## fmueller (Jan 11, 2004)

I am a great fan of the Eheim diffusor as outlet instead of a spray bar, because it provides great aeration. Here is how it works, and here you can see one in action, but I am usually setting it up for maximum current. In your case it might be best to have it directed against a rock or some such thing.


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## Ensorcelled (Mar 1, 2011)

fmueller said:


> I am a great fan of the Eheim diffusor as outlet instead of a spray bar, because it provides great aeration. Here is how it works, and here you can see one in action, but I am usually setting it up for maximum current. In your case it might be best to have it directed against a rock or some such thing.


Interesting. I have thought about using it before instead of the spraybar when I did acquire a classic, but my concern would be potentially a lack of surface agitation vs the spraybar. I use a surface skimmer with my fluval currently because without it, I had some pretty nasty surface scum because of the single outlet nozzle.


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## fmueller (Jan 11, 2004)

Ensorcelled said:


> Interesting. I have thought about using it before instead of the spraybar when I did acquire a classic, but my concern would be potentially a lack of surface agitation vs the spraybar. I use a surface skimmer with my fluval currently because without it, I had some pretty nasty surface scum because of the single outlet nozzle.


I hear you. I had a very similar problem when I ran a 2213 on a heavily stocked 200 liter (about 50G) mbuna tank back in the day. I also bought the Eheim surface suction extractor to combat surface scum. The surface suction extractor works well, but it is an eye sore in the tank, you have to switch it off when feeding, the thing is a hassle to clean, and so on, and so on.

When I upgraded to a 2217, I also got the diffusor just to try it out, and I dare say that $6 device made a bigger difference for me than the bigger filter. It provides for far better aeration, and that attacks the surface scum issue at the root, rather than just treating the symptoms. What I found is that with better aeration I would no longer get surface scum in the first place, hence there was no longer a need to remove it. All I can say is try it, you might like it :thumb:


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## Ensorcelled (Mar 1, 2011)

fmueller said:


> Ensorcelled said:
> 
> 
> > Interesting. I have thought about using it before instead of the spraybar when I did acquire a classic, but my concern would be potentially a lack of surface agitation vs the spraybar. I use a surface skimmer with my fluval currently because without it, I had some pretty nasty surface scum because of the single outlet nozzle.
> ...


I have also looked at the surface extractor and I have to completely agree...it really is a big ugly eyesore. I also don't like how much $ they want for it plus the fact that you apparently have to run a "t" connector or something so say Eheim. I might give it a try seeing as it's not expensive at all. I find it interesting how you got those results with just the aeration assuming you had it pointing downward like you have it setup with your 2260 on your 125G.


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## fmueller (Jan 11, 2004)

You get oxygen into the water at any surface between air and water. That's obviously the tank surface, but also the surface of all those tiny bubbles the diffuser injects into the water. If you have a few big bubbles, like you get from most air stones, the total bubble surface is still small and doesn't play a great role in the grand scheme of things. But the total surface area goes up drastically if you have a large number of small bubbles...

Also, in the same way as there are bacteria converting ammonia to nitrite and nitrate, there are other bacteria that break down organic material (hydro carbons). If that conversion is complete, the products are water (H2[/sub]0) and carbon dioxide (CO[sub]2[/sub]). The latter is consumed by plants or gasses out of the tank. Note how you need lots of oxygen (O) to turn all the hydrogen (H) into H[sub]2[/sub]0 and carbon (C) into CO[sub]2. If the conversion is not complete (for example because there isn't enough oxygen), you end up with various organics, and some of those form the oily layer that makes up your surface scum.

In short, a diffuser does not attack the surface scum. Through better aeration it prevents the compounds from forming that would eventually turn into surface scum. That is my theory anyhow


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## Ensorcelled (Mar 1, 2011)

fmueller said:


> You get oxygen into the water at any surface between air and water. That's obviously the tank surface, but also the surface of all those tiny bubbles the diffuser injects into the water. If you have a few big bubbles, like you get from most air stones, the total bubble surface is still small and doesn't play a great role in the grand scheme of things. But the total surface area goes up drastically if you have a large number of small bubbles...
> 
> Also, in the same way as there are bacteria converting ammonia to nitrite and nitrate, there are other bacteria that break down organic material (hydro carbons). If that conversion is complete, the products are water (H2[/sub]0) and carbon dioxide (CO[sub]2[/sub]). The latter is consumed by plants or gasses out of the tank. Note how you need lots of oxygen (O) to turn all the hydrogen (H) into H[sub]2[/sub]0 and carbon (C) into CO[sub]2. If the conversion is not complete (for example because there isn't enough oxygen), you end up with various organics, and some of those form the oily layer that makes up your surface scum.
> 
> In short, a diffuser does not attack the surface scum. Through better aeration it prevents the compounds from forming that would eventually turn into surface scum. That is my theory anyhow


Theory or not, that's still very informative, thanks for the post!

I'll be picking up a 2217 here in the next few days and I plan to run it with the stock media configuration it comes with (assuming its the best setup). I'll probably run the spraybar running the length of the tank like I mentioned and see how it does. If I decide to try out the diffusor I know I can get it relatively cheap!


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