required filter stages in auqaclears

[Soeman]

So I acquired a used auqaclear the other day for one of my empty tanks, and went to my LFS for a new filter. The sales person insisted that the sponge only provides mechanical filtration, and for biological filtration I needed to buy the other stage; they equally convinced that the carbon filter was an absolute neccesity. Knowing that the majority of sales vendors 'knowledge' comes from the suppliers, and thus jaded, i thought i'd come here for what i hope is unbiased advice.

1) I know the sponges _can_ provide suitable sites for the establishment of bacteria, but is it enough? Is the supplier's suggested 'biological filter stage' (which appears to be basicaly a bag of stones) the best option? an alternative would be to throw in a couple bio balls.

2) In general, is carbon filtration required?

[mdaigle]

I've been running AC filters for years with sponges only .... Shhhh don't tell my fish !!

Michel

[KLKelly]

I have a higher bioload tank with no plants.  I like the comfort level of having the biofilter media.  I've never had a crash (which is important with a PH of 9.0 ammonia is toxic at lower levels) and its super easy to seed other tanks.  I don't have carbon in my filter unless I'm removing medication or worried about a contaminate.  I do use purigen though.

I actually cut my sponges in half thickness wise and add more biomedia.  I have ammonia in my well water and my filters eat it up in a matter of a couple of hours.

[beowulf]

As with mdaigle I only use sponge in my filters and have never had an issue.

[fischkopp]

Sponges are just fine for bio-filtration. You can use any ceramic-type biomedias to increase the surface area and hence the filtration even more. I made a sandwich, like KLKelly: sponge-ceramic balls -sponge. I even put a little sponge in the chamber with the tube intake.

You don't need active carbon unless you want to filter any nasty stuff out of the water: medications, heavy metals, tannins, ...

[Soeman]

Thanks folks, you're giving me exactly the response I expected. Glad to know I was on the right track 

[tim_s]

I use sponge and bio media.
I will admit the bio media is more for me and my worries then it is for the fish.

[Laura]

I only use sponges in my AC filters too.

[bergenm]

I don't think it really matters what you put in your AC filter - sponge, carbon, am-rid, ceramics, pot scrubbies - whats important is that you only clean the media with used tank water. A couple of passes under the tap and the media become next to useless.

Personally I use the same sponge, carbon and ceramics that came with the filter when I bought them a couple of years ago - they are all now biological filters.

I would only replace the carbon or add am-rid if I was trying to resolve a specific problem with the water.

[mseguin]

I generally recommend to people to use the sponge, and biomax or other biomedia.