Filter media and Beneficial bacteria myth

Barry Tetra

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Hi everyone.

I’ve watching lots of video on youtube (most of them were sponsored)
And most people says that sponges does not contain any nitrifying bacteria and you should have biological media inside the filter instead, is this true? or was it just a gimmick that make you buy 1kg of pumice for 50$?

Some people also saying that you should have dirty sponge in your filter to grow a colony of anearobic bacteria that turns nitrate into nitrogen.

All of this gimmicky things that made you buy stuff is so confusing...

I also seems to get brainwashed by ADA sellers that sells aquascaping scissors for $200 at my LFS o_O
 
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Colin_T

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Sponges have lots of tiny little holes and spots that trap dirt. These spots also hold beneficial filter bacteria. When you clean an established sponge, you get rid of the gunk but leave the good filter bacteria behind to keep growing and cleaning the water.

An established sponge is a sponge that has been in an aquarium for a couple of months and the beneficial bacteria have developed a biofilm on and in the sponge. The biofilm helps the bacteria hold onto the bits of sponge.

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Anaerobic (lacking oxygen) bacteria cannot grow in most aquariums because there is too much oxygen in the water and the anaerobic bacteria cannot live in oxygen rich environments.

If you have large pieces of limestone or sandstone rock (at least 4 inches in diameter), you will get some anaerobic bacteria living in the middle of the rock. But the outer inch of rock will contain aerobic bacteria.

If you have 4+ inches of sand on the bottom of the aquarium, you will get anaerobic bacteria living in the bottom few inches but the top 1-2 inches will contain aerobic (requiring oxygen) bacteria.

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Dirt trapped in filter media/ materials like sponges is not helpful to the fish and increases the chance of a bacterial or protozoan infection occurring in the aquarium.

The dirt in filters is fish poop and that is home to lots of harmful microscopic organisms. The aquarium water gets pushed through the filter media and is constantly being exposed to fish poop and its associated microscopic organisms.

If you clean the filter media regularly, you get rid of the fish poop but keep the beneficial filter bacteria. And this means you have no problems with ammonia or nitrite, and the water is cleaner and has fewer harmful micro-organisms in because there is less fish poop in the tank and filter. Less poop means cleaner water and healthier fish.
 

Ichthys

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Pure gimmick. Any surface area in a filter will house bacteria. The millions of sponges in use kinda prove these idiots wrong.

Anaerobic bacteria are in the filter aswell if you have porous media. They’re Nitrobacter (or whatever we’re calling the nitrite-eaters these days) so they do indeed live in oxygen-rich water. If there isn’t enough oxygen they take it from nitrate, producing nitrite, and eventually (if the flow rate is slow enough) nitrogen.
 
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Barry Tetra

Barry Tetra

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Almost got branwashed if it’s not for TFF, thanks everyone for answering.
 

Wills

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The discussion around sponges vs biomedia is basically that in the same area you can get more surface area on biomedia than sponges. You only really need to use sponges as a pre filter so as the water comes in on the intake it hits the sponges of varying size to catch all the gunk basically. Which over time breaks down or gets rinsed out manually while the bacteria in the biomedia break down the chemical aspects of the nitrogen cycle.

A lot of these biomedias that are talked about on YouTube are very expensive like Seachem Matrix so there is definitely a commerical angle to it.

I raised this exact comment before and was put right - the idea being that your filter is only going to house enough bacteria for the ammonia and nitrite that is produced. So if your tank has a filter full of sponges and no bio media and it works there is no need to change it. But when I set my tank up I purposefully got Seachem Matrix to put in and threw out most of the sponges, it was very expensive and feels overload in all honesty but just something I wanted to do at the time.

In terms of the nitrate to nitrogen process I've not met or heard of anyone other than the YouTube channel who claims it to have achieved it. And when you think of all our members here... surely someone would have done it by now? Some of this guys videos on how to optimise filters are very good though and worth watching because some manufacturers really have slightly missed the target sometimes and with a few tweaks you get better equipment.

Wills
 

Ichthys

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Actually denitrifying filters (nitrate to nitrogen) are very straightforward and easy to make. You just need a lot of porous media to make a difference, because of the very slow flow rate required. I’ve made several over the years when I’ve had big fish, and they work really well.
 

Wills

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Actually denitrifying filters (nitrate to nitrogen) are very straightforward and easy to make. You just need a lot of porous media to make a difference, because of the very slow flow rate required. I’ve made several over the years when I’ve had big fish, and they work really well.
...well colour me stupid haha

Come on going to need more info than that please! When you say porus media do you mean things like Matrix or Pond Guru? And in terms of flow what sort of turn over did you use?

I've been looking into chemical options for this kind of situation but getting a biological process going would be much much better in the long run. Not for my current tank but for a future one I havent told my wife about yet ;)

Wills
 

Ichthys

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@Wills it really is that simple. All you need to do is give Nitrobacter water with no or very little oxygen in it. Without oxygen in the water they’ll get it from nitrate.

Nitrate -> Nitrite -> Nitrogen.

Any porous medium will work. They all have microscopic pores leading to a vast network of internal branching tubes which provide a huge anaerobic surface area.
Contact time needs to be long enough for the complete equation, otherwise the filter will pour nitrite into the tank. My first attempt (just a few litres of media with a flow that I couldn’t get slow enough) poured out 1ppm of nitrite.
My end result was a three gallon (UK) bucket two thirds full of porous media. The pump was the puniest little thing I could find, about a litre a minute, entering the bucket at the bottom (a pipe in at the top and down to the bottom),and exiting near the top at the other side. This gave zero nitrates for small fish, and matched production by big cichlids, pretty much.

So the three important key factors are enough media (quite a lot considering), slow enough flow rate (long enough contact time), and the media need to be kept scrupulously clean.
 

mjfromga

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I have seen people use containers within their tanks to foster an anaerobic environment and even with higher stocking levels... It helped keep their nitrates WAY down. I have experimented with this myself with success.

The key is to keep the container actually contained. Having a cup full of gravel that turns anaerobic can actually be beneficial... Until you flip that cup over and spill the contents into the actual water column. Then you have a major problem. For this reason, it is generally better to avoid anaerobic conditions in aquaria. An accident can quickly turn into a fish killing catastrophe.

It is similar to having filter sponges covered in algae and random organics... Not generally a major problem. BUT if you squeeze all the filth into the water column - bad things will happen.

Sponges do hold nitrifying bacteria, however I think a large amount of porous media is better than mostly sponges. I definitely have better success with way more porous media than sponges.
 

Wills

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This is so interesting hoping in the near future to get a cichlid tank in the region of 300 litres I have really high nitrate in my tap water but now have an RO unit but for big changes I’d prefer to do a mix and something like this would really help. Will need to pick your brains closer to the time
 

Avel1896

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To me, sponge media is only made for trap dirt/detritus. I clean them in tapwater.
On the other hand, the biological media I use (AquarioNeoMedia Pure) is check twice a year and clean in ROW if needed. I would change it for nothing else !
 

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