Carbon filter design?

[Jasontkd]

I am going to be making a DIY carbon filter form my tank. My question is: most filters that hold media, are all shaped like this:


Here the water is pumped through the top, down to the bottom, where it is forced back up through the carbon, and back out the top.

Why not something like this?


water is pumped to the bottom, forced through the carbon, and out the top. Is there anything I am missing? Is there something wrong with this design?

I will have it as a hang on filter that will hang on my sump. Is the first design just so the filter can sit flat?

any suggestions?

Thanks,
Jason

[Doug1]

That should work fine, i think that slow flow from bottom gives a better dwell time. Keep in mind that carbon will load up and need changing frequently, or it can leach adsorbed stuff abck into the tank, as well as becoming a bio filter after a while.

[Loverotties]

Yes carbon loads up fast.

[Doug1]

Have you thought about how you are going to construct this, you need to be able to seal both ends obviously, and install barbed fittings on both ends for the hose. You are also going to need some kind of screen at both ends to keep the carbon blowing through. You might consider putting the carbon in nylon stocking to make loading and cleaning easier

[xtopher]

I think that the only downfall is that if you lose power all the crud from the carbon load will be sucked down. Otherwise I don't see why they ALL do it that way but there has to be a reason.

[Jasontkd]

well, i am going to have Filter sponges and barriers to keep the carbon (and the crud) where I want it.

[Fly Guy]

You are losing the upflow principle in plumbing it that way. It will still of course work, but will not collect or retain the impurities you are trying to remove as well as if you used the upflow principle.

They are designed that way because it works better, not so the bottom is flat.

[Jasontkd]

how so? the flow still goes from bottom to top. How is it any different?

[Fly Guy]

Its different. Its even, thorough flow throughout all of your media with none of the channeling whatsoever that you will get from the input shooting up from the bottom. The channeling will load up specific areas of the media within the canister while not hardly touching others.

For this application how you have it surely will work, just not as efficiently for removal or for life before it needs changed out. Nor will it really harm anything per se in this application but do a search on the "upflow principle". You will see it used in other applications that demand that perfect, even, thorough flow throughout everything without channeling

[Harry_Y]

You could bring your water in the side instead of the bottom by using a "T" fitting.

They way the crud can settle on the bottom.

Good Luck!