# Calculating Tank Turnover



## ChilliPepper (13 Oct 2015)

I've read I need to aim for 10x turnover.

I have a 240L tank, with a Fluval 306 external filter which is 1150 LPH.

Do I need to add a powerhead? I can't remember the formula to work out the tank turnover!


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## Andy Thurston (13 Oct 2015)

yes 10x turn over is right which means you need around 2400lph so a powerhead is a good idea


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## ChilliPepper (13 Oct 2015)

How do I calculate the turnover?


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## Andy Thurston (13 Oct 2015)

pump flow divided by tank volume which means you've got 4.8 x turnover


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## Martin in Holland (14 Oct 2015)

That 1150 l/h is what the factory measures, keep in mind that they measure with an empty filter (no media in it).


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## ian_m (14 Oct 2015)

Martin in China said:


> That 1150 l/h is what the factory measures, keep in mind that they measure with an empty filter (no media in it).


The x10 rule takes that into account. Use the flow quoted on the outside of the box.

If you dig around in your filter instructions it may state the actual flow. This is for the JBL e1501 (quoted 1400l/hr on the box), so actual with clean media may be 800l/hr probably dropping off even more when dirty.


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## ScottW (15 Oct 2015)

Also when you talk about the 10x rule, if say your tank capacity is 500 l but you have substrate, hardscape etc could say take away 50-70l 

Would you calculate on the actual water volume or the potential capacity of 500 l  ? 


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## Andy Thurston (15 Oct 2015)

personally I work on the whole tank but if flow round the tank is good i don't think you need to


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## flygja (16 Oct 2015)

I'd just calculate the total tank volume, easier than trying to estimate the volume of hardscape, plants, filter media etc etc.


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## ChilliPepper (19 Oct 2015)

Thank you all. I will have to look for a powerhead. 

I need a quiet one as I am so pleased with my Fluval 306 filter, it is incredibly quiet, so don't want something to turn the tank into a noisy thing.


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## ScottW (19 Oct 2015)

I put a Fluval Sea C2 in mine at the weekend, it's silent and very compact. 

http://www.amazon.co.uk/Fluval-SEA-Circulation-Pump-1600LPH/dp/B009XSGI9C 


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## Paul Kettless (21 Oct 2015)

I have had a  Jeboa rw4 in one of my previous tanks, also quiet, and shifts a lot of water, has a controller too, so you can play with the flow patterns. strength etc.


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## Jake101 (21 Oct 2015)

You can also test the turnover rate in reality, if you want to, by letting the filter pump water to e.g. 1 liter box. Take time and then you can calculate the litres / hour. The pumping height affects a lot, so make sure that it is the same as in your aquarium.


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## herezor (5 Nov 2015)

Jake101 said:


> You can also test the turnover rate in reality, if you want to, by letting the filter pump water to e.g. 1 liter box. Take time and then you can calculate the litres / hour. The pumping height affects a lot, so make sure that it is the same as in your aquarium.


If you do that, what would be the recommended turnover?. I guess the 10x rule does not apply anymore in such case. Is it back to 3x or 5x or what?

Cheers

Pedro


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## ian_m (5 Nov 2015)

The x10 rule is based upon the rate stated on the box rather than the actual flow which will be less, especially if dirty.

Most decent filter manufacturers often quote the actual rate hidden away in the user manual. Here are the figures for JBL e1500 (1400l/h), e900 (900l/h) and e700 (700l/h) from the user manual.


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## LondonDragon (5 Nov 2015)

Filter turnover you don't necessary need 10X, you need enough flow around the tank to get the CO2 and nutrients to all the plants. Even having 10X turnover but with incorrect positioned spraybars or hardscape blocking the flow, you will still have problems. You just need to ensure the flow around the tank is adequate, a good method is to move your dropchecker around the tank every couple of days and monitor the reaction in various places to ensure that indeed the flow looks good.


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