# Juwel filter vs External



## durtydurty (2 May 2008)

Have a Juwel Rekord 80 litre with 5 tetra's, 6 platies, 5 Panda Cories and a Plec. 

Have a sand substrate over soil and even after cleaning it two days ago the fish waste collects in fairly large quantity on the bottom of the tank in a certain spot. 

Is this normal and would an external prevent this unsightly build up or is it a matter of fine tuning my setup? 

Any advice is greatly welcome.


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## Wolfenrook (2 May 2008)

An external will certainly help.  I have a Juwel tank, and my memory of the filter was that the majority of the intake was from slats at the water surface.  This wont do a lot for heavier wastes that sink.  You could try plumbing the external to one end of the tank, and then placing a flow pump/power head opposite, this should keep the detritus from settling to the bottom and create good currents to circulate nutrients and CO2, helping to avoid dead spots.

I personally don't like Juwel filters, in my experience they just aren't up to the job.

Ade


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## aaronnorth (2 May 2008)

more circulation is the key, the intake will consume the waste within a certain distance for example a radius of 10cm so in effect the larger the filter the larger the output of water (circulation)


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## ceg4048 (2 May 2008)

Yep, I agree. A properly rated throughput will do the trick. It churns the water and keeps particles suspended for a longer time. We all sort of agreed on 10X the tank volume per hour rating so something in the 800L/hr rating class would be great.

Cheers,


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## durtydurty (2 May 2008)

For that size tank what sort of filter would one recommend and would it be just a easy to remove the internal and get an external?


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## Wolfenrook (2 May 2008)

ceg4048 said:
			
		

> We all sort of agreed on 10X the tank volume per hour rating so something in the 800L/hr rating class would be great.
> 
> Cheers,



Except for me, who think that 10x the tank volume on larger tanks is insane.   

I find I get enough circulation using the pump/powerhead opposite the filter outlet technique, with the pump either pointing towards the front of the tank, or mounted at the front and pointing along the front glass, to create a continuation to the filter flow.  Also IMHO circulation wise if your flow is enough to keep medium sized detritus suspended then it is more than enough to circulate CO2 and nutrients, which are also aided by diffusion as well.  Advising 10x tank volume per hour in every case is, imo, not the best idea.  Not all species of plants or fish will enjoy such a fast current.  Eg in my tank to get that kind of flow I would need to use something like a Fluval FX5, which would lead to my settee getting wet and my fish spending most of their time whizzing around the tank insanely.   Considering that part of my stocking are dwarf gourami, which naturally live in fairly still waters, this would be far from natural conditions for them.

Ade

PS. Also note that upon showing my wife how much an FX5 costs, she showed me a suitcase, and asked me if I could locate the front door ok.  So I think I will continue on with my new JBL Crystal Profi 250 thanks. lol


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## ceg4048 (2 May 2008)

Well at least you didn't show here the Eheim price. You may not have made it to the door!   

The 10X is the filter "rating" which filters never deliver on their best days assuming they are filled with media and are mounted at typical locations below the water level. They normally deliver only about half of their rating. The real number we had was 3X-5X the tank volume in actual pump delivery. Instead of complicating life with calculating real versus rated it's easier to go with 10X rated or nearest available. The added advantage of a high filter rating is that you also get a high filter capacity in terms of volume.

Some find the additional powerhead solution obnoxious looking so it's easier to have this flow throughput from the filter as opposed to mounting another device. I agree with sending the effluent across the short axis (back to front) which really helps carpet plants. I advocate the use of spray bars mounted on the back glass which lowers the exit velocity and spreads the flow more evenly across the long axis. Multiple spray bars can be ganged to reduce turbulence further. 

The question though is what is enough and in what type of tank? A general rule of thumb ought to be good enough for most applications. 10X the filter rating _always_ works better than any head scratching associated with trying to adjust the recommendations for every conceivable tank configuration. Sometime you can get away with less or for one reason or another a 10X rating cannot be accommodated so just get as close as you can. Another issue to consider is that as the tank fills in with plant growth and with the inclusion of hardscape the flow distribution becomes blocked and stagnant areas can become more prevalent. Moreover, the added biomass of a few months growth will require more nutrient and CO2 delivery than was necessary due to higher biomass.

Certainly, smaller tanks, and lower lit tanks can get away with lower throughput. Non Co2 tanks in fact can get away with a lot less flow and filtration because things happen a lot slower in those configurations. But more flow is always better. Large tanks have a real problem with flow as there are huge stagnant areas due to energy dissipation of the effluent as it fills the space. In large highly lit tanks, flow is even more important. My tanks have always been on the large to very large side and I have empirical evidence that, all other things being as equal as can be, higher filter capacity and higher flow reduces the occurrence of algae or facilitates more rapid recuperation from an algal bloom.

I can safely guarantee you that if you did upgrade to an FX5, suitcase and settee notwithstanding, you would see a substantial improvement in water clarity, nutrient distribution and plant growth because you would be delivering nutrients/CO2 with greater efficiency, allowing your plants to produce greater levels of Oxygen, which would generate and support higher levels or aerobic bacteria - above and below the substrate - which in turn would accelerate nitrification. Of this there can be little doubt.

By the way, living on a brightly lit Hollywood stage in a glass box, being fed by hand several times a week in someones living room can hardly ever come close to being a natural habitat for any fish, but I do understand the issue of turbulence stressing this species.  

Cheers,


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