I notice that the new Fluval U4 can be bought more cheaply than the older 4 Plus. Why is this? I see the polyester is attached to a carbon pad which could mean expensive replacements, but I guess you can just use polyester if you wanted to. Why are the old ones still more expensive?

For anyone that has used both what do you think? I have the Fluval 4 Plus and really rate it but I need to get a new filter for my aquarium as I am now seriously thinking of having a go at breeding.

Look forward to hearing your views

Angela

Angela..

i just prefer the old over the new right now... know it's been a while since you posted....

the new one as a upright jet stream, where as the old one as the venturi effect on the top with a additional tube you place in the oulet spout.

to be honest i have never used the carbon filter at all ... so unsure about that..

i do rinse both out every week in old tank water, or may be every 9-10 days at a worse case scenario, though I have two filters periodically in my main two tanks...

I have both types the fluval 4 plus & the U4 i find the U4 to be much better than the 4 plus as it holds biological media which never needs replacing compared to just relying on sponges which break down after a while & when replaced you lose half your healthy bacteria even if doing one sponge at a time
For the best internal filter look at the new eheim biopower by far the best internal filter i have ever used with next to nothing in running costs, I would never buy the fluval again

Here is a link explaining the new version of the fluval U series: http://www.youtube.com/watch?v=qZbA6h1cCSI

Right here'smy take on the fluval's.....
They are both good filters for your average setup but i have had both and if your breeding BN's then stick to the old fluval 4+ as the new one has way too many BIG gaps in it, and i lost quite alot of fry due to this... ....for me the old Fluval's win hands down were BN's are concerned...