Is expensive bio media worth it?

[Maf 2500]

I suspect that the bacteria (etc) would consume some of the ammonia before the plants could take all of it.

I find it rather unlikely that the plants could mob up all the ammonia and leave nothing for bio filtration - it might be that the levels are low and the bacteria colony would just be smaller - the bio filtration would still work in your favor as a safety belt.

Exactly. The plants have no method of preventing filter bacteria (or substrate bacteria or whatever else) from sharing the ammonia until such time as all the ammonia is used up. At which point the plants would be able to consume the nitrates that were manufactured by the bacteria.

 

[erwin123]

Agreed. Regular filter cleaning is key... How do you measure NO3 level consistently btw.? My NO3 readings using the API test kit could be anywhere from 40 to 160ppm.... realistically its probably around 30ppm.

How so? if the bacteria colony is just reduced due to the competition with plants why would that make it a liability.

I agree. That is what I prefer as well. A massive plant to livestock ratio. I am starting to think of my filtration as mostly mechanical filtration and a source of flow and circulation and much less about the bio filtration given my plant mass, but I do not doubt for a second that some is happening and that it is beneficial.

Cheers,
Michael

While I agree that there are issues with Nitrate testing, my Sera NO3 test appears to give me consistent results in terms of the broad colours.

• Greenish-yellow (0 Nitrate tap water reference),
• Yellow
• Orange
• Red

When I increase my NO3 dosing, at the end of the week, the test shows a darker shade of colour. When I decrease my NO3 dosing, the test shows a lighter shade. Similarly, when my Nitrates are on the high side, eg: Orange, after I do a water change, the test colour shows yellow. This is what I understand as 'consistency'.

For example, recently I added root tabs and reduced water column dosing slightly - the test result colour is consistent with that - I am confident based on the way the test has performed that if too much nitrates leaked out into the water column, it would result in a darker colour shade for the NO3 test.

What is true is that I don't know how many ppm of nitrates corresponds to yellow, orange, red respectively. This may limit the test's usefulness if I was trying to achieve some sort of 'target' NO3 ppm (I'm not, I agree that all I need to know is how much I add, and how much my tap water has - and this also sort of corroborates the test colours - if my tap water is 0 Nitrates and I add 10ppm a week, there is no reason why the test should suddenly show 100ppm Nitrates for example - so far the test colour of yellow is consistent with my dosing regime).

But I still feel the test is using for checking that NO3 levels are stable - if every week your test shows yellow but one week it suddenly turns orange/red - maybe you have a decomposing fish somewhere that needs to be removed, problematic root tabs or something like that- water parameter instability being one of the possible factors in algae outbreaks.

 

[MichaelJ]

Sera NO3

Hi @erwin123 Interesting, I will try that out. My go to for gauging the general health status of my tanks is my TDS meter. If something is amiss it will register much faster (i.e. a sudden and unexpected increase in TDS) than the perceived health of the plants or fish will indicate - I think of it as taking the tanks blood pressure.

Cheers,
Michael

 

[jaypeecee]

How do you measure NO3 level consistently btw.? My NO3 readings using the API test kit could be anywhere from 40 to 160ppm.... realistically its probably around 30ppm.

Hi @MichaelJ

Good Morning!

The API NO3 Test Kit is notorious for being unreliable. I use the JBL NO3 Test Kit.

How so? if the bacteria colony is just reduced due to the competition with plants why would that make it a liability.

Because it will be dumping nitrate (and phosphate) back into the water. No?

JPC

 

[MichaelJ]

Hi @MichaelJ

Good Morning!

Good morning! @jaypeecee - Yes, it's past my bedtime here in Minnesota, US, but I had to finish some work

I use the JBL NO3 Test Kit.

I will try the JBL kit as well - if I can find it on amazon.com

Because it will be dumping nitrate (and phosphate) back into the water. No?

Wouldn't that be a marginal problem if there is very little biological activity going on in the filter in the first place?

Cheers,
Michael

 

[jaypeecee]

While I agree that there are issues with Nitrate testing, my Sera NO3 test appears to give me consistent results in terms of the broad colours.

Hi @erwin123

I've never used the Sera NO3 Test Kit. But, it's good to know that it is a potential alternative to the JBL NO3 Test Kit. There are some NO3 Test Kits that report the result as NO3-N. It is therefore necessary to multiply the measured value by 4.43 to convert to NO3. In the UK, one such example is the MA* AquaCare kit, which is manufactured by NT Labs Ltd.

* MA = Maidenhead Aquatics

JPC

 

[jaypeecee]

Wouldn't that be a marginal problem if there is very little biological activity going on in the filter in the first place?

Hi @MichaelJ

Perhaps. Only a controlled experiment would be able to determine exactly what is happening.

JPC

 

[jaypeecee]

My go to for gauging the general health status of my tanks is my TDS meter. If something is amiss it will register much faster (i.e. a sudden and unexpected increase in TDS) than the perceived health of the plants or fish will indicate - I think of it as taking the tanks blood pressure.

Hi @MichaelJ

I prefer to measure ORP*/Redox but whatever works for you.

The term 'TDS Meter' is a bit of a misnomer. The meter typically measures electrical conductivity in microSiemens/cm (or Imperial equivalent). It then makes some assumptions about the water composition and converts to a TDS ppm figure.

* ORP = Oxidation-Reduction Potential

JPC

 

[John q]

Hi jaypeecee.

This is something that I had not considered. Does Diana Walstad cover this in her book, Ecology of the Planted Aquarium?

I can only reference the 2nd edition, but yes it gets a brief mention on p107 chapter 7.

"Of 33 aquatic plant species investigated, most were found to prefer ammonium over nitrates. Because many terrestrial plants grow better with nitrates and some botanists successfully grow plants with nitrates should not weaken the fact that aquatic plants - given a choice - greatly prefer ammonium. Whether they grow better with ammonium is a separate issue - one that is not as critical to fish health or aquarium functioning. However, I would hypothesize that most aquatic plants probably grow better with ammonium".

In the next sub chapter she goes on to say..

"There are few studies comparing the effect of nitrates and ammonium on growth of aquatic plants than their "uptake preferences" discussed in the section above. The fact that plants take up ammonium preferentially from a mixture of ammonium and nitrates does not guarantee that they will grow better with ammonium".

I would prefer to let my plants be the sole aquarium water purifier. And this hopefully explains my curiosity and the reason for pursuing this topic.

I see no issue with this approach providing the planting and stocking levels are in balance.

 

[jaypeecee]

Assuming we have the <"other nutrients required for plant growth"> why would NO3 accumulate in a planted tank?

Hi @dw1305

Wouldn't this occur if NO3 is being produced (in the bio filter) at a rate greater than the rate at which it is being used by the plants?

JPC

 

[jaypeecee]

This is something that I had not considered. Does Diana Walstad cover this in her book, Ecology of the Planted Aquarium?

Hi @John q

When I replied to you as above, I had previously overlooked the bit about "...whether or not they grow any better when exclusively fed NH4..." (my italics). Of course, growth may not correlate with nutrient uptake.

JPC

 

[dw1305]

Hi all,

The plants have no method of preventing filter bacteria (or substrate bacteria or whatever else) from sharing the ammonia until such time as all the ammonia is used up. At which point the plants would be able to consume the nitrates that were manufactured by the bacteria.

Exactly, I've always said that while there is "microbe only" nitrification, that there isn't any "plant only", it is always <"synergistic "plant/microbe" biofiltration">.

"Of 33 aquatic plant species investigated, most were found to prefer ammonium over nitrates. Because many terrestrial plants grow better with nitrates and some botanists successfully grow plants with nitrates should not weaken the fact that aquatic plants - given a choice - greatly prefer ammonium. Whether they grow better with ammonium is a separate issue - one that is not as critical to fish health or aquarium functioning. However, I would hypothesize that most aquatic plants probably grow better with ammonium".

In the next sub chapter she goes on to say..

"There are few studies comparing the effect of nitrates and ammonium on growth of aquatic plants than their "uptake preferences" discussed in the section above. The fact that plants take up ammonium preferentially from a mixture of ammonium and nitrates does not guarantee that they will grow better with ammonium".

I think this is right, this time the <"one legged Irishman"> is in the <"all you can eat buffet">, he has run out of ribs, but he is still tucking into the vol-au-vents and he has just alerted his friends that there is free food available.

............. Wouldn't this occur if NO3 is being produced (in the bio filter) at a rate greater than the rate at which it is being used by the plants?

Yes, it would, you are then in the same neighbourhood as when you don't have plants (Spotte, below). In waste water treatment this is one of the reasons why you need a <"larger Constructed Wetland"> to deal with higher bioloads.

The major difference between planted and unplanted would be that the extra nitrogen will stimulate plant growth, which will then reduce nitrate levels in a negative feedback loop.

There is a review paper:
Ansari, A. et al. (2020) <"Phytoremediation of contaminated waters: An eco-friendly technology based on aquatic macrophytes application"> The Egyptian Journal of Aquatic Research, 46:4, pp 371-376

cheers Darrel

 

[jaypeecee]

Hi Darrel (@dw1305)

The major difference between planted and unplanted would be that the extra nitrogen will stimulate plant growth, which will then reduce nitrate levels in a negative feedback loop.

Would you mind explaining the above in a bit more detail? In particular, 'the extra nitrogen'. Where does that come from? I have no problem with negative feedback loops - they are used extensively in electronic circuitry, believe it or not.

JPC

 

[Aqua sobriquet]

Although my filters (Eheim and Sera) both came with Bio media I’d probably have bought it anyway. Both filters are of modest size running modest size tanks. They both have inmates as well. One has Corydoras and maybe 100 cherries and the other one maybe 50-60 cherries. If they didn’t have livestock then I wouldn’t bother.

 

[jaypeecee]

Wouldn't that be a marginal problem if there is very little biological activity going on in the filter in the first place?

Hi @MichaelJ

I'm not sure about that. There may be few, if any, active nitrifying bacteria. But, what about heterotrophic bacteria, which are plentiful in our tanks?

JPC

 

[Jaseon]

Could a heavily planted tank take the main role of biological filtration to the point any other filtration you have would end up becoming mechanical?

 

[dw1305]

Hi all,

The major difference between planted and unplanted would be that the extra nitrogen will stimulate plant growth, which will then reduce nitrate levels in a negative feedback loop.

Would you mind explaining the above in a bit more detail? In particular, 'the extra nitrogen'.

Apologies, probably not very well phrased, the "extra nitrogen" isn't a difference between the planted and unplanted scenario, it is just the accumulation of NO3 shown by the graph.

In the unplanted scenario it accumulates, and can only be depleted by <"water changes, anion exchange or anerobic denitrification">. If you like there is no-one to eat the Vol au vents.

The situation is different in the planted tank, that "surplus" of nitrate never occurs because it is incorporated into plant tissue, either initially as ammonium (NH4+) or as nitrate (NO3-), the end product of microbial nitrification.

How do we know that plants will take up that "extra" nitrogen? Because we can equate leaf colour (chlorophyll density) with nitrogen availability.

cheers Darrel

 

[arcturus]

What about plant only tanks? Ive heard of people having heavily planted tanks with no filtration.

This is a different topic. If the tank has only plants and no fauna, then the nitrogen-related toxicity plays virtually no role. You would need water circulation, especially if using CO2, but that can be achieved with pumps or power heads. A mechanical filter could be use the keep the water clear, but otherwise there is no need for a filter.

 

[John q]

If the tank has only plants and no fauna, then the nitrogen-related toxicity plays virtually no role.

Sorry to go off topic but... Nh4 toxicity to plants is something that plays a role. We should choose our words carefully when thinking ammonia/ammonium is some kind of plant god.

 

[Jaseon]

This is a different topic. If the tank has only plants and no fauna, then the nitrogen-related toxicity plays virtually no role. You would need water circulation, especially if using CO2, but that can be achieved with pumps or power heads. A mechanical filter could be use the keep the water clear, but otherwise there is no need for a filter.

Yeah i see it as different topic, just the conversation made me consider it.

It does make sense to me though that a biological filter could be rendered mechanical if the plants take up all the available food.