# External advice for a 24"x15"x12"



## Chris85 (16 Sep 2008)

Hello, i am looking for some advice regarding a choice of extrernal filter for my new 24"x15"x12" planted tank. I have been doing a bit of searching on this forum and it appears that the ideal turnover rate is around the 20x tank volume per hour rate, is this right? From that i am thinking something along the lines of 1000-1200lph would be about right. Now i have a spce issue in that the space in my cabinet is around 30cmL x 30cmW x 43cmH, so the filter has to fit into this space. I have been looking at the Tetratec 1200 which i like and the Fluval 405, are these any good? 

Any advice much appreciated,
Chris.


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## jay (16 Sep 2008)

Can't imagine my 405 in my little 24" tank. I guess with a lot of media and maybe an external heater along the out take line would bring down the turnover a bit.
I've got a Fluval 205 on my same size tank and it turns over the tank just fine.


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## Garuf (16 Sep 2008)

I'd go for the 405, I know the woe of having insufficient flow.


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## Chris85 (16 Sep 2008)

Ok, i will be using a Hydor external heater so that will brig down flow a bit. I am looking at such large filters because i have been reading that it can combat dead spots that cause algae and distribute C02 and ferts to the leaf surfaces more efficiently. Is this correct?

Regards,
Chris.


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## Garuf (16 Sep 2008)

it is indeed. It's something to do with "boundary effect". I personally don't understand it in the slightest but I'm certain a search will throw up some useful info.


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## ceg4048 (16 Sep 2008)

Hi,
    The 10X tank volume per hour is a rule of thumb that helps deliver nutrients to the plants. There are a lot of factors which determine how well plants grow in the tank but the more flow and better distribution you have the more forgiving the tank is and the less likely you are to suffer deficiency syndrome which can lead to algae outbreaks. This is not a magic pill and it doesn't mean that you can be completely sloppy about everything else. You still need to dose appropriately, you still need to be careful with your lighting and CO2 and you still need to perform water changes as well as tank/filter maintenance. This does not mean that you will fail if you have less flow rating, just that life is easier with higher flow and better distribution, especially as the plants fill in and start blocking the flow. Having a filter rating of 10X the tank volume does not mean that you will achieve that flow. When everything is connected frictional losses mean that the filter will only deliver about half of it's rating. We've taken all this into account and came up with the nominal 10X rating. If you don't want to deal with the nitty gritty of the science of flow then just remember more flow is better than less flow and leave it at that. Either of the two filters you mentioned will be fine.  You can lessen the turbulence by using the spraybars and if this is still too strong you can either drill additional holes in the bar or gang together additional bars (I like this solution better). The larger the tank the more critical the issue of flow is.

Cheers,


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## Chris85 (16 Sep 2008)

Hello, i will be using a lilly pipe so hopefully that should spread the flow more instead of having a strong jet.

Regards,
Chris.


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## Ray (16 Sep 2008)

Go for 10x or 12x circulation in a 65 litre tank so you need 650 - 800lph.  To fit in the space either an Eheim 2224 or 2026.  Dimensions and throughput are here but I find them bigger in reality, perhaps this is just the base - so take a tape measure to the shop to be sure:

http://www.aquatics-warehouse.co.uk/extras/eheim/eheim_info.html

I think 20x is overkill and in any case won't fit in your small cabinet.


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## Garuf (16 Sep 2008)

Don't get a 2224, mine isn't powerful enough for my tank which is just 3" smaller.


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## JamesM (16 Sep 2008)

Garuf and I had this same conversation the other day... I have the same size tank and I've had to run 2 EX700's rated at 700 lph each.


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## Garuf (16 Sep 2008)

Where as I run a single 700lph, and would you believe it I have algae!


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