Fluval U3 filter sponges/carbon pad changes

[Negseven]

Hi, have got replacement sponges and carbon pads for this filter (not going to touch the biological media in the filter yet) whats the best way to change out these sponges/pads without crashing the tank, I’m assuming it will be one at a time, any ideas on timelines? Thanks

 

[Essjay]

I would leave the sponges in there, they'll hold a lot of bacteria, and just wash them in old tank water. The only reason they say to change them is to make money. Sponges last for years.

For the pads, they are a layer of carbon impregnated fibre stuck to a layer of floss, I think? If that's right, peel them apart and just use the floss part. Put the carbon half in the cupboard. When the floss part falls apart, replace with a layer of filter floss/wool. You can buy that in metres cut off a roll (Amazon, eBay) and use a pad as a template to cut it to size.
The floss part catches fine particles which go though the sponge and biomax, and carbon is not needed on a routine basis.

 

[Negseven]

I would leave the sponges in there, they'll hold a lot of bacteria, and just wash them in old tank water. The only reason they say to change them is to make money. Sponges last for years.

For the pads, they are a layer of carbon impregnated fibre stuck to a layer of floss, I think? If that's right, peel them apart and just use the floss part. Put the carbon half in the cupboard. When the floss part falls apart, replace with a layer of filter floss/wool. You can buy that in metres cut off a roll (Amazon, eBay) and use a pad as a template to cut it to size.
The floss part catches fine particles which go though the sponge and biomax, and carbon is not needed on a routine basis.

So I could in theory do the same to a new one (carbon pad) I have got and should be good to go? Must be better having a brand new one (well actually it is from a third party and cheaper)

 

[Essjay]

Yes, you could use the new pads this way. Since the pads are thin they won't hold as many bacteria as the bigger sponges and biomax. Filter floss/wool doesn't wash very well as it tends to fall into holes so it is usually replaced regularly, before it has chance to grow many bacteria.