# Filter media criterias



## blue_francis14 (Dec 9, 2008)

Hello,

I am trying to research on filter medias and only found few information regarding it. Most of the documents I found are about filters itself, not the filter media.

As you know, there are three main types of filtration. They are mechanical, chemical and biological. And for the filters that are commonly bought in fish stores, they are the over head filters, box filter and the undergravel filters. There are some the sells canister filters, hang over back and some others. These filters have a limited capacity for filter media and we want to make the most of that space and would like to choose the optimal filter media.

So here is my question, what are your criteria in buying filter medias? 

Below are the criteria that I have found to be important.


Surface area per cubic volume
Size of the filter media

I know that a combination of the three main types should be made but I would like to find out the best filter media of each type of filtration.

Just like choosing a car, you have power, fuel consumption and price.

Care to share more criteria?

P.S. This is not market research.  This is a personal research to get the optimal solution


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## emc7 (Jul 23, 2005)

You are on the right track. But you really can't talk about media without talking about the filter. So add "suitability" or something like that. Really fine media like floss, diatomaceous earth filters and 'micron' filter pads do a excellent job at catching really small debris, but clog if run with a nice, strong flow rate for any length of time. In a air-driven sponge-filter, you want really fine cells for maximum area. In a power-head driven sponge-filter, the fine foam will collapse. You have more flow, so less surface and more stiffness is optimal. Sand is excellent in a pond-filter, but no good in a hang-on-back with a bottom impeller. 

And there is total volume. In a little filter, you need really efficient media (lots of surface area), but in a huge sump, you can use cheap stuff and still have plenty of filtration. 

I might add easy of cleaning and time to replacement (affects cost). Can you simple rinse it? Does it need "recharging" or bleaching before it can be reused. Is cleaning it such a pain that you'd rather throw it out. 

The reason there are so many choices is that there are pros and cons to each one. Tell us more about you plans so we can help you optimize you filtration.


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## blue_francis14 (Dec 9, 2008)

Hi emc7! Thank you for you input this really helps me alot. Actually, I just wanted to collect data from other aquarist. Like you said, there are pros and cons to each filter media. 

Here is what I have collected:


Surface area
Void space/clogability
Price
Durability/Life span

These are the factors or the criterias of filter medias. What I am planning is to have quantifiable number for the other criterias like clogability or something to make decision making much concrete.


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## blue_francis14 (Dec 9, 2008)

Update from what I have been researching, ceramic rings such as sera siporax, eheim substrat, it has 18000+ surface area per cubic feet. So what are disadvantages of the aside from the price?


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## lohachata (Jan 27, 2006)

undergravel filters also work well..one of the most efficient filtration methods available..
relatively maintainance free and reasonably priced..


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## blue_francis14 (Dec 9, 2008)

hi lohachata. I think you have misread my post. I more concerned with the filter media, not the filter itself. So the filter media would be the gravel? Is this a good filter media to other filter types?


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## lohachata (Jan 27, 2006)

the needed bacteria lives on all of the surfaces..the finer the gravel ; the more surface area for the bacteria...the more bacteria ; the better..the gravel works quite well as the media..and very much cheaper that all of those ceramic bits they sell..
you could also use gravel in other types of filters..box filters with floss work nicely..put gravel in a piece of nylon pantyhose or in a media bag..place it in a HOB or even in a canister..
when you are not wealthy ; you learn how to do things a little differently..and often that means doing them in a more natural way..which is better for the fish.


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