# Alternative to Fluval U4



## Pricey32 (1 Jan 2018)

Title gives it away a little bit but im after an alternative to the fluval u4, Im tired of all the crap getting stuck behind it so when you take it off to clean it all flies out then having to desperately scramble to try and collect as much as you can. Then to make matters worse you alway get that one small fish bright enough to swim into the mount and the back of it but the cant manage to get its way out so then your constantly checking the back. Any better alternatives??? please help


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## BubblingUnder (1 Jan 2018)

I had a similar problem but with the Fluval U3 (same design but an internal filter a size smaller). The Fluval U3 had only small sponge media on either side of the filter it used to clog very easily. Personally I think that the old Fluval 3 was better & easier to maintain.

Why it seems to be hard for a major manufacturer to design a decent internal filter with a larger sponge capacity I don't know but I swapped my Fluval U3 for an 'Ocean Free Hydra 30' in the end. I would assume the Hydra 40 would be a good alternative but you would have to double check its suitability.


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## dw1305 (1 Jan 2018)

Hi all, 





BubblingUnder said:


> Why it seems to be hard for a major manufacturer to design a decent internal filter with a larger sponge capacity


I've often wondered the same. If you get an <"Eheim Aquaball"> or <"Eheim Biopower"> you can add extra sponge modules, but it is quite an expensive option.

That was why I started to use the power-head/ Koi sponge combination, and I still think these are the "internal" filters that give you most bang for your buck.






There are some other options at <"http://www.sponge-filter.com/">, and there are similar sponge blocks at <"Swiss-Tropicals">

cheers Darrel


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## Millns84 (2 Jan 2018)

I'm running a Ferplast Blumodular 3 on my 240 litre tank - Excellent piece of kit, supplied with coarse, medium and fine sponge and you can also buy extra modules for around £7.00 for extra media.

I've also got an Aquael Turbo 500 on my 40 litre tank - Another great filter but I probably prefer the Ferplast.


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## GeorgeR (2 Jan 2018)

Not sure about the mounting with regard to fish getting stuck at the back, but i have my eye on one of these for my 45L by Oase https://www.amazon.co.uk/dp/B01FJQ2Q4W/_encoding=UTF8?coliid=I1ZHNWXRIFAPGS&colid=QQUNM7IIJEQ2&psc=0

There external filters look good also. Decent price and good reviews.

Like the idea of the heater being combined within the filter. Not sure if they do one big enough for your set up though.


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## Edvet (2 Jan 2018)

I've used a filter like Darrel's in a 50x50x50 cm for years and years, Soundless and foolproof.


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## Millns84 (2 Jan 2018)

Would this be of any use?

https://charterhouse-aquatics.com/s...owqBSzIagp5QxuNsmVSQ5sJ5HbpWbAtBoCj3sQAvD_BwE


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## Johnn (4 Jan 2018)

I have some suggestions to improve the fluval u4 use.

Buy a sheet of poly pad foam such as aqua one poly pad. Cut a square almost the size of the top of the filter(looking down from above) and place it on top of the 3 trays before you close the main lid as there are few gaps where unfiltered water passes straight through resulting in blocked bio media, impeller damage.

Cutting and using your own thicker poly pads in place instead of the poly/carbon inserts work well.

Also sliding poly pad or course foam behind the filter mount/holder prevents small fish entering the abyss at the back of filter.

Vacuuming the sides of the filter while performing wc keeps it cleaner for longer.

That aquael above looks good may give one a try, wonder if you can get poly pad into it before the bio media

I found the (old)original fluval 4+ internal filter to be more powerful and included flow indicator, but I don't remember there being any compartment for bio media?
Both of them and every internal filter I've used has released debris when removing, I find turning them off and hoovering before removal helps.


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## sciencefiction (5 Jan 2018)

I've had a couple of the U4 filters for years, still running. I only ever had one fish getting stuck behind and its been years, and many fish. It was an ottocinclus. I guess it got carried away while cleaning the glass.... It was actually behind the U2 version which has a lot smaller gap(I've got two of them too), not U4. I fixed the issue by cutting a thin layer of sponge and inserting it behind. The alternative I suggest is an external filter. As for internals, you probably won't get a filter as reliable as the U4s.


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## Millns84 (17 Jan 2018)

Johnn said:


> I
> That aquael above looks good may give one a try, wonder if you can get poly pad into it before the bio media.



That's exactly what I've done on my Aquael Turbo 500. I've also replaced the ceramic rings with Eheim Substrat Pro as he small size allows you to pack more in.

Excellent and very reasonably priced filters. The optional extras such as LED UV steriliser and spray bars are an added bonus.


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