Which filter media to use for your goldfish tank filter?
There are three basic types of filter media to consider when deciding which to use inside your aquarium filter:
Biological media
This type of media is most common in the form of ceramic or glass noodles and bio balls. The sole purpose of this media is to facilitate the growth of bacteria to break down various toxins in the water.
The rule of thumb with biological media is the more porous the surface of the media the better the facilitation of bacteria growth. There is a limit to the effectiveness though and if the media is too porous it can clog and become relatively useless.
Mechanical media
Mechanical media is simply any media that is used to catch debris in the water column. When undisturbed it also acts as a biological media as the porous surface promotes bacteria growth however it is not as efficient for growing filter bacteria as traditional biological media.
Mechanical media is usually in the form of sponges and poly pads of varying fineness. The more course the pad the less debris it will pickup. The finer pads collect more debris but will require cleaning more often as a result as they clog faster.
Chemical media
Chemical media via the use of chemical reactions is usually used to treat the water or achieve a desired effect. There are a number of uses of chemical media such as toxin and medication absorption, polishing of water and water parameter stability.
One note with chemical media is that carbon in particular is so good at removing stuff from the water that it will take out good nutrients too, so if you have plants they will potentially be starved until the chemical media “fills up” and stops working.
Chemical media comes in various forms but is usually either carbon or a carbon derivative infused with certain chemicals to achieve the desired effect.
When stocking your filter with media, it is important to know what media the filter comes with so you can assess whether you need to order any additional media.
For example when I bought my Fluval 305, it came with sponge media, 2 baskets of ceramic noodles, 2 baskets of carbon and 2 empty baskets. Not needing the carbon I decided to buy enough biological media to fill the four empty baskets. I also bought a sheet of fine poly sponge to catch fine particles and cut out sheets of them to place on top of the bio media on the top two baskets.
With goldfish tanks I recommend either the noodles or the bio balls in your biological filter area. Don’t worry about carbon, you don’t need it and it usually reaches peak absorption in two or so weeks anyway. I personally prefer ceramic noodles over bio balls as I find you can squeeze more in. Poly pads (fine sponges) can be found in most fish shops or hardware stores, is sold by the sheet and inexpensive.
When placing filter media inside your filter generally speaking you want your mechanical media to filter the water first, then biological media to clean the water and then any fine mechanical or chemical media to be the last thing the water passes through.
If you really insist on running some sort of carbon in a goldfish tank, I highly recommend you run Seachem Purigen. It doesn’t touch trace elements in the tank like carbon does (depriving plants of nutrients), can absorb a LOT more toxins then carbon and is rechargeable to boot.
Purigen is a fair bit expensive then carbon initially but the fact it can be recharge quickly negates any price difference given carbons average life span of two weeks. The recharge process is simply a matter of soaking the purigen in a bleach solution and then rinsing it thoroughly. Do follow the instructions though as it can be rendered useless if recharged incorrectly.
There are a lot of options to consider when stocking your filter media, so have a think about it and take into consideration your individual tanks’ needs when deciding which media and how much of it to use.
Don’t have a filter yet? Not to worry, why not have a read of my filter articles to help you decide which one is the most appropriate for your tank;
Leave a Reply