Filters and Axolotls

Boomsloth · Mar 21, 2014

Hey everyone, So I got into a discussion with someone about what different filters are best for an axolotl.
First, filters are not necessary! They can provide circulation and a home for beneficial bacteria, but the bacteria will adhere to any and all surfaces within the tank as well.
A tank will cycle without a filter and axolotls have no problems with this set up.
Now to the part about filters that I had the discussion about..
All filters will produce the same amount of nitrate regardless of which one is used in the tank. This is true with no filter as well. It seemed logical to me that if an axolotl is producing a set amount of ammonia, common sense dictates that the nitrate would be the same. So all water changes should be similar as well.
There are nitrate reducers but those can get somewhat complex.

I would like to hear people's opinions, experience, and general maintenance requirements for their axolotls water quality. I'm hoping this helps inform those that may not understand the purpose of the cycle and how filtration works for/against it.

Kaini · Mar 21, 2014

How difficult is it to actually hold a cycle without a filter though? I was under the impression substrate just couldn't hold enough beneficial bacteria to sustain a cycle. And the bacteria like heavily oxygenated water, like what flows through the filter - turning your filter off for periods of time will kill the bacteria, so how....?

I've never had a tank cycle without a filter, so I'm genuinely curious as to how this is accomplished. Has anyone done it?

But about the other point yes - no matter how powerful your filter is, there will only be enough beneficial bacteria as your bioload. As much ammonia is being produced, that's how much bacteria there will be. The rest 'starve' so even if you have a HUGE filter or something, you'll still have the same amount of bacteria as if you had a smaller filter in the same tank with the same number of animals (say one lotl). so same amount of end product, nitrate would be logical I suppose...?

xxianxx · Mar 21, 2014

Kaini said:
I've never had a tank cycle without a filter, so I'm genuinely curious as to how this is accomplished. Has anyone done it?

It cycles the same as a filtered tank though it may take a bit longer, I have a number of unfiltered tanks and they are generally heavily planted to strip out nitrates. Filters aren't essential in an axolotl tank but they are recommended for new keepers who aren't familiar with maintaining water quality or those who choose to have heavily stocked tanks.

mackinthebox · Mar 21, 2014

I disagree, there may be lots of surface area in an aquarium but it does not compare to the surface area of the filter media in a powered filter
you also need circulation to run the water across that surface so the bacteria may feed
a tank will not properly cycle and maintain that cycle without some type of filter with media
you run the risk of cycle crashes, ammonia spikes, and other issues that could seriously impact the health of your axolotls and fish

Elise · Mar 21, 2014

mackinthebox said:
I disagree, there may be lots of surface area in an aquarium but it does not compare to the surface area of the filter media in a powered filter

Having sand as a substrate, for example, would provide more surface area than most biological filtration media.

Kaini · Mar 21, 2014

Huh, definitely interesting.

auntiejude · Mar 21, 2014

I would always recommend a novice uses a filter, but an experienced keeper can do without. I personally have filters in all my tanks.

While the benficial bacteria live in substrate a lot of axie keepers use a bare bottom tank, which is possibly where the 'you must have a filter' message comes from.

All filters will produce the same amount of nitrate regardless of which one is used in the tank

While technically true - i.e. the ammount of nitrate depends on the amount of ammonia produced - the speed at which this happens does depend on the size and type of filter. A small filter with a low flow will take longer to convert ammonia to nitrate than a bigger filter or higher flow rate pump.

And the bacteria like heavily oxygenated water, like what flows through the filter - turning your filter off for periods of time will kill the bacteria, so how....?

Yes, if you turn a filter off for any length of time the bacteria will die off. But they don't require high levels of oxygen, they require a constant supply of ammonia. Turning the filter off effectively starves the bacteria because they quicky exhaust any ammonia if their water isn't moving when the pump is off. This doesn't happen to bacteria in substrate because tank water is always moving even without a filter pump.

mackinthebox · Mar 21, 2014

Elise said:
Having sand as a substrate, for example, would provide more surface area than most biological filtration media.

I would agree with this but only if youre using an undergravel filter, if you are not forcing water through the sand then you are only using a small fraction of the surface area...

Elise · Mar 21, 2014

auntiejude said:
Yes, if you turn a filter off for any length of time the bacteria will die off. But they don't require high levels of oxygen, they require a constant supply of ammonia. Turning the filter off effectively starves the bacteria because they quicky exhaust any ammonia if their water isn't moving when the pump is off. This doesn't happen to bacteria in substrate because tank water is always moving even without a filter pump.

I want to pose a question to you. How are the bottled nitrifying bacteria able to survive packaging when they do not have access to any food (ammonia or nitrite), and the oxygen level in the liquid bottle is dropping? They have been proven to have a shelf life up to a year, remember.
The bottled bacteria enter a dormant state called viable but nonculturable and I see no reason the bacteria wouldn't do the same in your filter. From everything I've read, the bacteria involved in the nitrogen cycle are incredibly robust and when a cycle crashes it is usually caused by a chemical introduction or by drying out the media.

Boomsloth · Mar 21, 2014

auntiejude said:
While technically true - i.e. the ammount of nitrate depends on the amount of ammonia produced - the speed at which this happens does depend on the size and type of filter. A small filter with a low flow will take longer to convert ammonia to nitrate than a bigger filter or higher flow rate pump.

How does this work if in a cycled aquarium the conversion is very rapid? If a low flow delayed the reaction then there would be ammonia in the water. This is assuming all situations have cycled so the bacteria are sufficient for bioload.

Velice · Mar 21, 2014

Boomsloth said:
How does this work if in a cycled aquarium the conversion is very rapid? If a low flow delayed the reaction then there would be ammonia in the water. This is assuming all situations have cycled so the bacteria are sufficient for bioload.

She said it depends on the amount of ammonia produced. If the amount is low there wont be much difference. If the amount is high then more water flow over thee bacterial colonies in the larger filter would convert faster as the larger surface area in the media would allow for better propagation.

Boomsloth · Mar 21, 2014

Velice said:
She said it depends on the amount of ammonia produced. If the amount is low there wont be much difference. If the amount is high then more water flow over thee bacterial colonies in the larger filter would convert faster as the larger surface area in the media would allow for better propagation.

Ammonia is assumed to be equal in both situations. Every one NH3 is converted into one NO3-, so yeah more ammonia means more nitrate.
It doesn't matter what size the filter media is, the population of bacteria would be equal if the ammonia source is equal. The difference in surface area provided only comes into play if its too small to support the colony needed for the bioload. The only time ammonia builds up in a tank, is when the ammonia source increases and there is a delay while the bacteria multiply to compensate.

xxianxx · Mar 21, 2014

"a tank will not properly cycle and maintain that cycle without some type of filter with media"
Incorrect. A tank will maintain a cycle without a filter, just consider the filter as a safety net to deal with ammonia spikes. If an unfiltered tank has a low stocking density, live food is used and full of plants you can actually have a low maintenance tank. This is a typical setup for many aquatic newts who don't like water flow. The problem with axolotls is their size, if people have too many in an unfilteted tank it can't deal with the amount of ammonia produced.

Cole Grover · Mar 21, 2014

For people newer to keeping aquariums and other enclosed aquatic systems, I'd certainly recommend a filter. All filters are not created equal, however. I've used everything from canisters filters and hang-on-back power filters to fluidized bed filters, to sponge filters, to protein skimmers and wet/dry filters, so I speak with some confidence on this subject. For nitrification, surface area is everything. It is hard to beat the efficiency and simplicity of a well-outfitted power filter of canister filter as far as biological or mechanical (or chemical, for that matter) filtration go. The porosity of the biological filter media (I'll use ceramics for this discussion), in conjunction with the water flow, create an ideal situation for nitrification. Sponge filters are OK in the biological filtration arena and are great for animals requiring low-flow, but just can't hold up to the efficiency of a power filter loaded with high-porosity ceramic media. The surface area to volume ratio achieved by pumping the water over the ceramic media is unparalleled for its simplicity.

Now, that said, a tank, tub, or other container will cycle just fine without a "traditional" filter. I now run "low-tech" set-ups for all of my Ambystoma mexicanum, though I use high-tech filtration for other taxa, especially those that tolerate or appreicate more water flow. Here's how I do it: All of my A. mexicanum are maintained individually, except for breeding introductions or when rearing groups of neonates. They are kept in bare-bottom plastic tubs, each outfitted with one to several moderatly-sized Spathiphyllum aroids. The Spathiphyllum (Peace Lillies) are grown hydroponically in perforated plastic pots filled with LECA (light expanded clay aggregate; "Hydroton"). The perforated pots allow free flow of water through the LECA and Spathiphyllum root system. The porous nature of the LECA allows ample space for the colonization of aerobic nitrifying bacteria (Nitrosomonas, Nitrospira, Nitrobacter, etc.). Spathiphyllum were chosen specifically for their tolerance (preferance, even) for emergent growth and their previously-demonstrated ability to rapidly and effectively remove nitrogenous wastes from aquarium systems. They also tolerate lower light situations, like those found in most homes. I've seen large beds of them used to remove the nitrogenous wastes from aquarium systems. They work well, though I'm certain other species, especially other aroids, would work, too. The plants also grow quickly and seem to be constantly in flower. I do weekly water changes, consisting of 50% one week, 100% the next. I also remove detritus as it appears. All nitrogenous wastes register zero using commercial test kits (though laboratory analysis would probably detect the trace concentrations transiently present).

In essence, this sytem is very much akin to the situation found in the "natural" habitat of Ambystoma mexicanum, where marginal, floating gardens known as chinampas have been utilized by the tradtional farmers in the Valle de Mexico for many, many years. These chinampas rely on the natural fertilizers (such as nitrogenous wastes produced by fish, axolotls, etc.) found in the Lake Texcoco complex (now reduced to canals and ponds of Xochimilco) for growth. The plants win and the water quality wins... or at it did historically, prior to draining most of the lake complex and dumping all sorts of nasties into it....

Just a few thoughts.
-Cole

auntiejude · Mar 21, 2014

Elise said:
I want to pose a question to you. How are the bottled nitrifying bacteria able to survive packaging when they do not have access to any food (ammonia or nitrite), and the oxygen level in the liquid bottle is dropping? They have been proven to have a shelf life up to a year, remember.
The bottled bacteria enter a dormant state called viable but nonculturable and I see no reason the bacteria wouldn't do the same in your filter. From everything I've read, the bacteria involved in the nitrogen cycle are incredibly robust and when a cycle crashes it is usually caused by a chemical introduction or by drying out the media.

As far as I'm aware the bacteria in the 'dormant' state are effecively in suspended animation - they would use some kind of chemical treatment as the way decapsulated brineshrimp eggs are preserved. The bactera do not require oxygen or nutrition in this state. Or possibly some dormant state similar to fungal spores that can survive for years until conditions are right for them. I'm not a microbiologist, but either of these 2 would be a good explanation for 'bottled' bacteria.

In a filter the bacteria are not treated in this way, they are live and will die if starved of food.

Boomsloth · Mar 21, 2014

Cole Grover said:
For people newer to keeping aquariums and other enclosed aquatic systems, I'd certainly recommend a filter. All filters are not created equal, however. I've used everything from canisters filters and hang-on-back power filters to fluidized bed filters, to sponge filters, to protein skimmers and wet/dry filters, so I speak with some confidence on this subject. For nitrification, surface area is everything. It is hard to beat the efficiency and simplicity of a well-outfitted power filter of canister filter as far as biological or mechanical (or chemical, for that matter) filtration go. The porosity of the biological filter media (I'll use ceramics for this discussion), in conjunction with the water flow, create an ideal situation for nitrification. Sponge filters are OK in the biological filtration arena and are great for animals requiring low-flow, but just can't hold up to the efficiency of a power filter loaded with high-porosity ceramic media. The surface area to volume ratio achieved by pumping the water over the ceramic media is unparalleled for its simplicity.

Now, that said, a tank, tub, or other container will cycle just fine without a "traditional" filter. I now run "low-tech" set-ups for all of my Ambystoma mexicanum, though I use high-tech filtration for other taxa, especially those that tolerate or appreicate more water flow. Here's how I do it: All of my A. mexicanum are maintained individually, except for breeding introductions or when rearing groups of neonates. They are kept in bare-bottom plastic tubs, each outfitted with one to several moderatly-sized Spathiphyllum aroids. The Spathiphyllum (Peace Lillies) are grown hydroponically in perforated plastic pots filled with LECA (light expanded clay aggregate; "Hydroton"). The perforated pots allow free flow of water through the LECA and Spathiphyllum root system. The porous nature of the LECA allows ample space for the colonization of aerobic nitrifying bacteria (Nitrosomonas, Nitrospira, Nitrobacter, etc.). Spathiphyllum were chosen specifically for their tolerance (preferance, even) for emergent growth and their previously-demonstrated ability to rapidly and effectively remove nitrogenous wastes from aquarium systems. They also tolerate lower light situations, like those found in most homes. I've seen large beds of them used to remove the nitrogenous wastes from aquarium systems. They work well, though I'm certain other species, especially other aroids, would work, too. The plants also grow quickly and seem to be constantly in flower. I do weekly water changes, consisting of 50% one week, 100% the next. I also remove detritus as it appears. All nitrogenous wastes register zero using commercial test kits (though laboratory analysis would probably detect the trace concentrations transiently present).

In essence, this sytem is very much akin to the situation found in the "natural" habitat of Ambystoma mexicanum, where marginal, floating gardens known as chinampas have been utilized by the tradtional farmers in the Valle de Mexico for many, many years. These chinampas rely on the natural fertilizers (such as nitrogenous wastes produced by fish, axolotls, etc.) found in the Lake Texcoco complex (now reduced to canals and ponds of Xochimilco) for growth. The plants win and the water quality wins... or at it did historically, prior to draining most of the lake complex and dumping all sorts of nasties into it....

Just a few thoughts.
-Cole

This right here was the ultimate purpose of this thread. Thank you for providing the species of plant as well!

Velice · Mar 21, 2014

If you wanted more information, it's called aquaponics. It is reliant on the numerous parts not failing to be successful which is its greatest disadvantage.

Elise · Mar 21, 2014

auntiejude said:
In a filter the bacteria are not treated in this way, they are live and will die if starved of food.

That's not true. If you were to remove the food source from an established aquarium you would still be able to keep a cycle for weeks. The death of the bacteria would be due to predation and not starvation. You can't starve the nitrifying bacteria.

It had long been assumed that a bacterial cell was dead when it was no longer able to grow on routine culture media.
We now know that this assumption is simplistic, and that there are many situations where a cell loses culturability but remains viable and potentially able to regrow. (oliver 2004)

Cells enter the VBNC state as a response to some form of
natural stress, such as starvation, incubation outside the
temperature range of growth, elevated osmotic concentra-
tions (e.g. seawater), oxygen concentration, or exposure to
white light (Oliver, 2000c).

NadeZ · Mar 21, 2014

Very interesting topic. I had never considered, but can't see why a tank would not maintain it's cycle with bacteria housed in the substrate. However, I would expect a number of issues with this. My man concern with running a tank without a filter is the lack of flow. The bacteria on the surfaces and substrate need flow to supply them with food and oxygen, while also removing waste products. So you would still need a powerhead.
In addition you would have to be careful not to remove too much substrate during cleaning, as I imagine this would be the primary site of bacterial colonization.
This is all generalized but there is one large issue specific to our axolotls. Since you would be using the substrate as your biological media, the flow would need to be directed at the substrate. This is going to be stressful for your bottom-dwelling axolotl. A filter allows the high flow rate desired by the bacteria, in harmony with the low flow rate (especially at the bottom) desired by the axolotl.
Would love to be corrected by someone with more experience in this area but I would expect an unfiltered tank to be much more unstable and more stressful for the axolotl, compared to the convenience (at a price) of a filtered tank.

mackinthebox · Mar 22, 2014

for everyone saying that you dont need a filter please, post up pics of your tank without a filter, then post your water parameters over the course of a week or so and lets see just how well your filterless system works against one with a filter...
otherwise no one has provided any direct evidence supporting this assertion

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