# Which Eheim Classic filter is good for a 55 gallon tank?



## PMD (May 3, 2005)

I'm making the move up to an Eheim and need to know what size to buy. I also have a few other questions about these if people can answer them:

1) Where exactly are people putting the filter floss in these? Do you bag it?
2) Can I also stick Purigen in there?
3) If I get a larger size, can I run it on a dimmer switch to control output flow?
4) Where can I get the pre-filters to keep shrimp out of them?
5) Would you recommend running pressurized CO2 through a reactor in the Eheim output or using a diffuser for this size of tank?


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## Squawkbert (Jan 3, 2007)

I'd go 2215 or 2217. I have a 2215 on my 46g and it's fine unless it's really due for a quarterly back-flush. If you want more flow, 2217 should be more than adequate.

1) Where exactly are people putting the filter floss in these? Do you bag it?
I don't, but you can if you want to - I got a kit from BigAlsonline and am using the Eheim provided stuff, less the carbon pad. After my second teardown, I added a layer of potscrubbers to the bottom to keep things snug.

2) Can I also stick Purigen in there?
Yes, if you want. If you want it separate from other media, use an additional (thin) pad on top of it, adding it to the top of the stack.

3) If I get a larger size, can I run it on a dimmer switch to control output flow?
Probably not. A dimmer will limit voltage, it won't modulate frequency. If I'm guessing right, these things all run at an RPM that's a direct result of your house's 50-60Hz (US) AC power. If you run it on a dimmer, it will just do the same until it quits turning. If you need less velocity from the spraybar, drill the holes out SLIGHTLY (you can always make 'em bigger).

4) Where can I get the pre-filters to keep shrimp out of them?
Sponge, Nylon bootie or combo thereof...

5) Would you recommend running pressurized CO2 through a reactor in the Eheim output or using a diffuser for this size of tank?
I feed 2x1g DIY into my 2215 intake. It works well.


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## PMD (May 3, 2005)

You are awesome! 

I guess I'll be going with the 2217 then. Thanks!


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## kwc1974 (Jan 4, 2006)

I would use the 2217 as well
Great filter and it is an Eheim...what more could you say


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## houseofcards (Feb 16, 2005)

Another option would be to go with the Ecco line. A Eheim Ecco 2236 would be good for that tank. I've had one on my 72g for over two years and love it. The Eheim Ecco line has some of the more modern conveniences such as separate trays for media and is self priming.


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## longhornxtreme (Feb 20, 2007)

I use a 2217 (gasp) on my 29G.  

I would definitely go with a 2217 on your 55. I just stick filter floss at the very top and let the plastic 'grate' hold it down. If you wanted to bag it I don't think it would be an issue.


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