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Discussion Starter · #1 · (Edited)
I know there are all kinds of rules of thumb. Some are put out by manufacturers, others by hobbyists based on years of experience. But is there any more scientific check to determine the amount of Biological Filtration Media needed in a tank? Or is just really a hit and miss sort of thing?



For example, I figure I might just as well buy a few more bio balls to throw into my filter because it's Saturday, they're on sale and what the heck you can never really have too much!


BUT that raises the question, How would I ever know if I have too little?



Of course, in an extreme case the fish my might racing around the tank while ammonia burns their gills.

BUT how about in the case where a little more would helpful or beneficial to the stability of the system but the tank isn't showing any immediate signs of distress.


Thankful for any thoughts or suggestions.
Michael
 

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My understanding is that a stable tank supports X amount of bacteria. If you have 1 litre of media, 2 litres or 10 litres, you will still only have X amount of bacteria because this is the amount needed to process the waste from the tank. So it isn't possible to have too much filter media, but the more you have, the more sparsely populated it will be with bacteria and so this space could have been better used for other purposes (sponges, filter wool, Purigen, etc). Having additional media does of course give room for the bacteria colony to grow if needed to cope with higher waste levels (e.g. fish stock increased).

Also not all media is equal in terms of bacteria housing capacity so you might need 5 litres of plastic bio-balls to do the same job as 0.5 litre of Matrix, or something like that. And not all bacteria live in the filter either; a significant portion might be inside the tank in the substrate etc.

Worth checking the manufacturers recommendations on the packaging. 1 litre of Seachem Matrix is apparently good for an 800 litre aquarium (but I probably put more than 1/4 litre in each of my 11 litre tanks!).

If you have stable zero ammonia and nitrite levels in the tank after it is fully cycled then I assume that means you must have sufficient bacteria and hence sufficient bio-media.

If it's a new tank setup, then checking whether a certain amount of added ammonia (say 2ppm, depending upon your intended fish load) is processed within a certain time frame (say 24 hours?) is a good way to check that both the cycling is complete and that there is a good enough size of bacterial colony.

I usually work backwards when planning my filter: first work out what sponges, filter wool and space for Purigen / charcoal / etc I need, then fill all remaining space with decent bio-media.
 

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snails are your friend
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Every square inch of substrate, hardscape, even the interior glass walls of your tank is surface area that BB will colonize on. In planted tanks, the nitrogen is uptaken by plants pretty quickly and there is typically less need for biological filtration, all other things being equal. And while they work fine, you don't need to buy bio balls. Nearly anything will do; lava rock, plastic army men, ladies hair curlers... the more surface area, the more inhabitable space.
 

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Every square inch of substrate, hardscape, even the interior glass walls of your tank is surface area that BB will colonize on. In planted tanks, the nitrogen is uptaken by plants pretty quickly and there is typically less need for biological filtration, all other things being equal. And while they work fine, you don't need to buy bio balls. Nearly anything will do; lava rock, plastic army men, ladies hair curlers... the more surface area, the more inhabitable space.
Oh gees. I just imagined a canister filter full of plastic army men. :laugh2: . Made me lol at work.
 

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Discussion Starter · #5 · (Edited)
Hey, thanks for the suggestion. Does anyone know where I an get a liter of army men? Do you think the color might matter?

I guess in terms of a "test" it would be tracking and testing for ammonia levels.

So, for example, if you're way off the fish will show signs of obvious distress. That's an obvious sign and you don't need to further test.

But what if only there's only a "little" too much ammonia?

Would that show up as increased algae growth?

I've heard that algae is great at quickly metabolizing ammonia.

I wonder if you could catch those fluctuations in ammonia levels using a Seneye monitor?

And if the Seneye could detect fluctuations or spikes in ammonia would that mean you need to add (or your tank could benefit from) additional biomedia?

Anyway, thanks all for sharing your thoughts.
 

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Any hard media is basically terrible for your biological media. The media must be permeable and have the ability to pass water completely through it quickly. The best media to use is 10/20 ppi foam or simple plastic pot scrubbies. Info is here.

http://aquariumscience.org/index.php/7-filter-media/
http://aquariumscience.org/index.php/7-1-1-filter-media-in-depth/
http://aquariumscience.org/index.php/7-1-3-filter-media-test/

And more data on this site...
Eh, I might say that some forms of media are less efficient than others, but lots of people use "hard" media and it gets the job done. Perhaps it's not the #1 best choice ever, but if it's effective I have a hard time calling it "terrible".

Also I have read through that website before and I would not take it as gospel. There's some good advice and information mixed in with a lot of strongly worded personal opinion. The author claims to be a research scientist and maybe they are, but the website is not written in a scholarly way, even though it postures like it is scientific.
 

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Completely agree with @Blue Ridge Reef. Once the tank establishes itself between all surfaces especially the substrate and plants you have all the bio-filtration you need. This is the case in most setups where you have a typical size canister and tank. The filter really becomes to me anyway a flow device and it doesn't really matter what's in it. Before the tank matures the filter is a great place for chemical media that will fill the gap until the tank matures. After that I typically fill with floss on the cheap.
 

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Yeah, my canisters are full of foam. Whenever I buy an Aqua Clear, the first thing I do is toss the bio rings. They just take up space when used on a planted tank, IMO. In the case of Aqua Clears, if you actually used all 3 provided medias, they barely even fit, two sponges fit perfectly.
 
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