Water Flow - Juwel Filter Vs External Canister

[coolie]

I have heard some criticism over my internal Juwel filter and someone else said my flow was no good for a planted tank in one of my videos.
 
 
On my other tank, however, I do have a Fluval External filter with the pipes which hang over each end of the tank.
 
What I don't get is that the flow is rubbish in that tank with the big external filter. What I mean is there appears not as much surface movement even
though on paper the pump has a major through put.
 
So I am wondering is there really any benefit of switching to an external filter to improve flow?
 
Today I messed around with some rigid piping to try to "direct" the flow out of the juwel filter so that the water moved it bit faster and had some success with that.

 

[milosilo]

External filters are almost always better than an internal. It doesn't have to be limited by size so holds better parts and a larger volume. In turn this increases the overall volume of your tank with an external. Make sure you set your externals output on high though, as many can be adjusted. Also, try and point the output towards the surface as this will agitate the water and also let you know its working. Saying this, I have a Juwel Rio 125 in my bedroom, and I never removed the internal filter as the flow on it is really powerful. It causes a real flow around my tank. I think the internal Juwels suffer on the larger capacity tanks.

 

[three-fingers]

With regards to flow on a planted tank - pretty much any single filter would give too poor flow!
 
You are aiming for 10x the tank flow rate per hour, most people don't want to spend money on a needlessly huge filter, so just add extra circulation pumps . 
 
For example, a 100L tank should have a minimum of 1000lph to ensure flow is good in all areas of the tank. The Fluval 205 external filter is rated for tanks up to 200L, but only gives 680lph, so even on this theoretical 100L tank the 205 would still need supplemented by an additional minimum of 320lph pump.
 
On my 80l tank I have a 480lph external filter plus a 1600lph Hydor Koralia circulation pump, and could still do with more, so don't worry about having too much flow!

 

[coolie]

But I don't think my fish would like it. Although they sometimes play in the flow, fish such as Neons often stay in a sheltered spot in the middle under some wood.
 
How have you found a slower flow rate affects plant growth with CO2?

 

[three-fingers]

But I don't think my fish would like it. Although they sometimes play in the flow, fish such as Neons often stay in a sheltered spot in the middle under some wood.
 

 

The fish will adapt very easily, and will probably benefit from the greater overall filtration and oxygen in the tank. Also, if your smart with powerhead positioning, or buy a modern circulation pump/wavemaker, its not a problem. Modern circulation pumps like the Hydor Koralia/Fluval Sea/Tunze Nanostrea ect. provide a wider, more evenly spread out flow that is slightly more comparable to what would be found in nature. 
 

 
How have you found a slower flow rate affects plant growth with CO2?

Very badly! If you have inadequate flow, your basically wasting your injected CO2 as your plants wont be getting it . On the other hand it would be a great way to grow algae on your plants, low flow is one of the most common reasons people have poor plant growth or algae issues.
 
Your Juwel filter is a great biofilter for processing ammonia from fish - but this is unneeded in a planted tank. Its specifically designed to have a low flow... suited for some fish don't mind, but very bad for plants.
 
Injecting CO2 and then not providing adequate flow to distribute to the plants is basically wasting CO2 IMO. I'd be looking at a circulation pump for Christmas  .

 

[coolie]

three-fingers, thank you for this very informative post, it's helped me a lot. I am removing the fluval external from my tank I am discontinuing and connecting it to my planted tank.
 
I need some kind of "suckers" or something to hold the pipework in situ. On the other tank, they are just hooked over the edge. I need the flow to go down the length of the tank. Any advice on pipe work placement and holding it in place appreciated.

 

[three-fingers]

No probs, glad it was of some use!
 
Adding the external to the tank sounds great, and I've been there before with Fluval pipework!  While its great that the hose doesn't kink, it can be a pain to install on some tank rims.  I had a real awkward time fitting my Fluval 405 ribbed hose over my 3" thick tank rim!  I hooked the  Fluval brackets to the tank rim on their sides instead of vertical and had to buy some of these to redirect the hose outlet/inlet.  I could take a pic if it helps, but I'm not sure this solution is applicable to your situation without seeing it. 
 
Do you have the Fluval brackets with suction cups that clamp the hose over the edge?  Fluval sells extra suction cups for the ribbed hose, though they aren't strong enough to hold the hose without the brackets.
 
Not sure if this would help either, but in case it is useful, depending on which Fluval you have, you could replace hose with non-ribbed stuff of either 12mm/16mm diameter or 16/22 diameter. You may find an easier way to hold this stuff in place.
 
An additional tip would be to run the canister nearly empty of media, as this will greatly increase the flow provided (the manufactures flow ratings are done without media in the filter). Non-ribbed hose would also increase the flow-rate slightly, if you do go down that route 

.

 

[coolie]

This is what it looks like with both the internal juwel filter and a Fluval 406. I know the pipe looks a little bit ugly. I had to make the suction cup for it out of a coat hanger and  a bathroom suction cup. There were none
specifically for it in the shop. The flow is amazing and the fish obviously love the flow and play in it. This has coincided with my CO2 running out over xmas, so I have lost that for a few days.
 
The fluval 406 was intended to take over fgrom the Juwel internal however, the Fluval was off the other tank for 4 days before I got it reconnected so needs time to re grow it's bacteria.

 

[coolie]

Has anyone else ended up running two different types of filter intentionally or otherwise? I was thinking of leaving it like this. I also discovered there's some sponges missing out of the fluval 4 (it was second hand).

 

[Garbolino]

in my 240ltr tank I have the internal jewel filter & a fluval 406 external I found the outlet was to powerful for my angels so changed the outlet pipe for a fluval fx5 twin pipe

 

[coolie]

That's amazing that you have exactly the same tank as me, the filter that came with it and the extra filter combination. Plus, do you think the Rosy Barb above has a guilty expression?

 

[ShinySideUp]

Nothing wrong with Juwel internal filters, I had one for years and it was deadly silent and rock solid, also easy to maintain. Keep it and add a power head.
 
As an aside, I wonder where this 10 times tank capacity an hour comes from? That is a massive flow rate. In my 640 litre tank I would need to have a filter that would turn over 10,000 litres per hour (so the media would bring it down to, say, 7000 lph and that is plainly just a nonsense; all my fish would be pressed against the glass on the far side of the aquarium!
 
I think 3x per hour would be perfectly acceptable, anything much higher would contribute nothing as the bacteria in the filter wouldn't have time to process effectively.
 
I use a Fluval FX5 (rated at 2600 lph, but more like 1800 lph with filter material) and everything has been running fine for nearly a year in this tank now.