I'm using ceramic rings as filter media for biological filtration.

For a given aquarium size, how many grams of the ceramic filter media do I need?

The packet doesn't have sizing instructions. I also cannot find any guidelines on line.

I know that stocking levels will affect how much you need, so for the sake of this question assume 1 inch of fish per gallon of water (as per common stocking recommendations).

  • How large is the tank?
    – Jestep
    Oct 4, 2016 at 18:09
  • I'm asking for a recommendation relative to tank size in grand per litre, or grams per gallon. Therefore the size of my tank is not needed to answer the question.
    – trampster
    Oct 4, 2016 at 20:23
  • 2
    There really isn't an answer then as far as anything academic I've ever read. The quick and dirty would be enough to harbor sufficient bacteria to process the ammonia produced in a tank. Realistically, I think it's probably only a fraction of of what we actually use in our filtration systems, but as far as I have ever seen, there no studies I've seen regarding it. Additionally, the surface area per ring is going to vary based on the brand and the material they're made from. Just a simple g / L would likely only be applicable to a single brand of ceramic ring.
    – Jestep
    Oct 5, 2016 at 17:32
  • 1
    you will simply have to find a balance where the amout of ceramic media dont affect the rest of the filtermedium negativly. May 3, 2017 at 17:50
  • As stated in some of the answers, there are many variables. Two of the key variables to know is the surface area per volume or gram of bio-media and expected amount of feed per day. The page biofilters.com/websize.htm outlines the calculation process for a large system with a trickle filter. Dec 18, 2017 at 6:00

5 Answers 5


Biomax = 1 ceramic ring per gallon (3.78 L). As stated numorous times that's just a rough estimate but to be safe, at a very minimum one per. 1 biomax ring = at least 100 ft2 (9.3 m2) so that's a lot of area per little ring. I use about 3 per gallon, but I'm always like that


It is not possible to answer this question, there are too many variables.

First of, all ceramic rings have different sizes and different manufacturers have different types of ceramic. Ceramic filter media or other types of filter media have different surface size depending on type and brand. The reason for using ceramic or other large surface types of filter media is to give bacteria a place to break down waste to ammonia and then to nitrite before converting nitrite to nitrate (plant food). So this means more filter media can handle more waste products from more fish.

Here is some useful information, even if it doesn't answer your exact question.


As a general view on this, as long as they fit in the filter and don't block or disrupt the flow through it it's a good amount. I don't think there's really a set "x amount of rings per gallon" kind of deal, atleast not that I've ever heard of. I have these rings on the bottom section of my filter in my small tank and I've just stocked them to optimally fit the space they occupy without hindering the waterflow.

  • 1
    And what if I'm making my own filter? How do I know how much I need? Because that will change how big I make my filter and how much space I allow for filter media.
    – trampster
    Oct 4, 2016 at 20:26
  • I only have internal filters but the rings take up around 30% of the filter I'd say. The rest is filled with sponges of different types. Oct 5, 2016 at 8:33
  • @trampster.when it comes to filters bigger is better and 30% ceramic rings is often used by manufacturers so use this amout.i built my own pondfilter it is 1000liters and it contains 3 pices of foam each 1 sqare meter and 15 cm thick,for my pond that is 30000liters. May 3, 2017 at 18:08
  • forgot to mention 150 kg of lava rock 25%volume,same funktion as ceramic but cost way less. May 3, 2017 at 19:25
  • If the lava rock is not in the filter then it won't be getting any where near the same flow over it and so it's not as effective as the ceramic rings in the filter. Dec 30, 2017 at 9:52

So a good sized filter for a tank will turn the water over around 5 times in an hour, or once every 12 minutes. So this should help you plan out an appropriate sized filter/pumping system.

Once you've done this, it's basically 'standard' to use 1/3rd of your filter capacity for biomass rings, this is the part which the bacteria in your filter will inhabit. The water should flow over/through this when passing through your filter - it's not enough for the rings to simply be on the bottom of the tank or such.

The other 2/3rds are used for sponges/filtering materials such as fibre mats / other additives.

  • Filter turnover is dependent on your pump not the size of your filter. So knowing I need to turn over my water 5 times an hour doesn't tell my how big my filter should be only how fast the water needs to flow.
    – trampster
    Jan 10, 2018 at 3:44
  • normally the filter and pump are one unit, if you're experienced enough to be choosing separate ones then you should already know how to calculate the right amount. I'll add a note about having the pump giving reasonable flow through the filter, but 'reasonable' is based on experience - there's no strong evidence that I know of to decide how fast the flow needs to be for filtering. Jan 10, 2018 at 12:48
  • I'm more interested in building my own filter from scratch, the 5 times per hour is a great guide for sizing your pump not for sizing your filter. The 1/3 is ring guide is great for determining how much of your filter should be rings, but again not how big your filter should be and therefore doesn't tell you the actual amount of rings you need.
    – trampster
    Jan 10, 2018 at 20:27

4 bio rings in 5 gallons (19 L) of water is more than enough to start the bio cycle to cultivate beneficial bacteria in 4 to 6 weeks.

  • 1
    Hi, thanks for answer, could you please include some references as to where do these numbers come from?
    – lila
    Jul 27, 2020 at 17:38

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