Fluval U4 Poly Carbon Cartridges

[Spamamos]

Morning All,

Tank is up and running and is I believe around the mid point of its cycle.

I don't want to disturb the bacteria too much and am not keen to do any water changes as i have TSS in the tank. Water parameters are all reading fine, I have noticed however that my aquarium water has a few bits and pieces floating around in it which are a new feature. My filter is second hand and the pads were not replaced when I picked it up, media is the old media also. I am not too worried at the moment but was wondering..

Is it maybe time to replace the pads?

These are what I would be changing.

https://www.amazon.co.uk/dp/B00GGHRAP4/?tag=

I also added two of these to the filter when it was started up.

https://www.amazon.co.uk/dp/B01G5H9VI8/?tag=

Thoughts would be very much appreciated on when or if it is necessary to replace any parts on the filter.

Thanks!

Spam

 

[Essjay]

If it were me, I would replace the polycarbon pads with plain filter floss/wool. You don't need to run carbon full time.

There should also be sponges and a central box of biomax. They just need washing in old tank water until the fall apart or crumble. I wouldn't bother with any other 'special' media like the second link.

 

[Spamamos]

Ok cool - where do I get the floss / wool from? So should I just fill the central space with biomax?

 

[Colin_T]

Sponges are better than filter wool/ floss. You can buy filter sponges from any petshop and cut them to size & shape with a pr of scissors.

 

[Spamamos]

Ok I'll speak to my LFS and see what they have/recommend and what their experience is.

I just tested my tank and came back with 0 Ammonia , 0 Nitrites and somewhere between 10 & 20 ppm Nitrates. Definitely not as red as 40 but hard to tell between 10 & 20.

Assuming this means the tank is cycled and it's time for a bit of a water change? If yes during the change I will clean the filter, are there any areas I should really avoid cleaning? Don't want to disturb the new bacteria colony.

 

[Essjay]

Since the polycarbon pads appear to thin, you may have trouble cutting a sponge to the same dimensions. Sponge would be better but if you can't make a sponge to fit, you can buy filter wool aka filter floss of a roll from an LFS and buy only the length you need.

I would definitely put biomax in the box in the middle - this is ceramic noodles. But don't change everything at once. There are three things to change - 2 polycarbon pads to sponge or filter wool and whatever is in the box to biomax. Do one, wait a month, do the second, wait a month and do the third.

 

[Spamamos]

Ok - i'll probably do the wool first since the Bio Max is my main biological filtration source?

Mechanical filtration seems to have less risk when replaced?

When I do add more BioMax I only want to remove a percentage I assume, so that my bacteria can colonise the new pieces?

 

[Colin_T]

What sort of filter is it?
If it's an internal power filter you should be able to replace the media with one sponge unless it's a really weird one.

 

[Spamamos]

Fluval U4 - it's internal.

 

[Colin_T]

Damn, what have Fluval done?
Talk about over complicated. Whatever happened to powerheads with big sponges on them?
Try to put sponges in anywhere you can but I don't know where you can on that

 

[Essjay]

Do you have biomax in there now?

The media for the U4 should be:
on each side a plastic frame holding a foam or sponge pad in each
next, moving inwards, there should be a polycarbon pad on each side
in the middle should be a box filled with white ceramic noodles - biomax.

The outermost sponges held in the frame should last for years. They will need replacing when they go holey and shapeless. Until then, squeeze them in old tank water. When they eventually do need replacing, do one first then the other a month later.
The biomax will only need replacing when it starts to crumble.
The polycarbon pads look from photos to be a layer of filter wool glued to a layer of something impregnated with carbon. You may find these will only wash a few times before falling apart. If this happens you will need to replace them, but I wouldn't bother with buying the Fluval pads as they'll work out expensive. Either see if you can cut some sponge to the same size and shape, then just wash them as they get dirty, or get some filter wool (aka filter floss) and use that instead. This won't wash properly so you'll need to replace it fairly regularly but as you can buy it by the metre or yard (depending on where you live) it works out a lot cheaper than buying Fluval pads. You don't need to use carbon, plain filter wool is fine.

 

[TallPaul]

Activated carbon will come with most all new filters but it's only really required for removing chemicals. Once your tank is stable you can get rid of them.

If you need to medicate the fish then you should put carbon back in so that any residual medicine does not linger in the water

 

[Ch4rlie]

Essay has pretty much nailed it, no point in buying expensive Fluval brand filter sponge or so called filter cleaner.

I am a fan of Fluval filters, have had u2 and U3 in the past and does exactly what it says on the tin and access is pretty good.

I normally had the usual sponge and bio media and every week I changed the filter floss when doing a water change. Pretty cheap stuff and you can buy these in a large roll and cut to size for your filter compartments.

This is one example of what I’ve used in the past without any issue at all, just do a quick rinse of the cut out part before adding to the filter -

https://www.ebay.co.uk/itm/2m-AQUAR...a1c76ab1660ac88f304073dffff4f31&ul_noapp=true

 

[Spamamos]

Do you have biomax in there now?

The media for the U4 should be:
on each side a plastic frame holding a foam or sponge pad in each
next, moving inwards, there should be a polycarbon pad on each side
in the middle should be a box filled with white ceramic noodles - biomax.

The outermost sponges held in the frame should last for years. They will need replacing when they go holey and shapeless. Until then, squeeze them in old tank water. When they eventually do need replacing, do one first then the other a month later.
The biomax will only need replacing when it starts to crumble.
The polycarbon pads look from photos to be a layer of filter wool glued to a layer of something impregnated with carbon. You may find these will only wash a few times before falling apart. If this happens you will need to replace them, but I wouldn't bother with buying the Fluval pads as they'll work out expensive.

This is exactly what I have yes.

Ok, so I'll add more biomax to the middle cage, replace the inner carbon type pads with filter floss and leave the outer sponge until it starts to fall apart. Obviously not all at once but that's the long term plan.

Thanks guys!

 

[Colin_T]

...If you need to medicate the fish then you should put carbon back in so that any residual medicine does not linger in the water

Just clarifying this point. Carbon should be removed when using fish medications or plant fertilisers because it will absorb them. However, after treating fish, you can put carbon back into the filter for a few days to absorb any residual chemicals.