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N is high in fish food relative to P. So P will always be in a lower ratio to N as far as plant needs.

Carbon is quite another issue entirely. Far more carbon as CO2 will enter through the air above than the food source. That carbon source is stored and eventually will be used by algae, plants, or gassed off, just like C02 enrichment. We have done Carbon tracer studies at UC Davis here. The Carbon atoms can be traced through a systemand relative % of each source of carbon, such as the % ratio from fish food and the % from the air and other sources can be determined.

Also, the tap water and the source water for water changes plays a huge role. Simply feeding more vs changing the food type may give you the same results, I suspect prior, you were N limited, rather than some C/N ratio issues.

Tom Barr

2,069 Posts
@tom said:
Well I agree , with you Tom that P is often a limiting factor.
But using our feeding method will free up all plantnutrients accept K.
Well, you have to add enough of the nutrients in a balanced ratio for a given growth rate otherwise this will not be true.Carbon is not part of this equation in terms of __plant growth__ which is what I stated previously.

Carbon as an electron donor can be limiting in some soils with little organic content, eg the bacteria are carbon limited, this is not the same as "CO2" limited. Plants are never carbon limited in this senmse, they are autotrophes, wereas the bacteria in the referenced paper are heterotrophes.

@tom said:
The proces consist of 2 steps that, when combinend result in lower needs of plantnutrients.
I am not clear what you are are saying here. You get the same plant growth with less nutrients? The nutrients still need to come from somewhere ansd the rates of plant growth are directly related, there is no way around a simple 2 box model, what goes in MUST come out.
Food in, plant growth out.

@tom said:
First, you slowly change from your current fishfood source to using frozen food species
with a low C - N ratio such as Mysis and Bosmina.
This will result in faster and total microbial decomposition.
So your bottem becomes cleaner and higher amounts of elements can be used by your plants.
Well this is bacterial decomposition/remineralization. A good substrate, filter, water changes etc will facilitate that. Carbon can be limiting to the bacteria in a NEW tank, I suggest adding some peat and mulm from an established tank for this precise reason, the bacteria need some carbon to live on, new tanks are often lacking. But in an established tank, carbon is non limiting as the bacteria play a decreased role since the plants use up the nutrients. All the bacteria are doing for you then is taking bound organic carbon and oxidizing it to CO2.

Which is my point in my last post.
The N is going to be used up by the plants once the fish excrete the waste as NH4+.
Plants will not use the Carbon, they will use some of the CO2 once the bacteria cycle it.
See if you can measure any NH4 in a well run plant tank.

@tom said:
It's research I'm very familar with, I've studied this precise topic in depth at UF in grad school with the top person in the world in biogeochemistry in wetland soils, Dr Reddy.
Your application of this research is what I'm questioning here.
The fish waste is a very labile form of DOC, plants are not DOC limited. bacteria can be. As you increase DOC and POC, this places a strain on the O2 levels, these increased cycling rates by these heterotrophic bacteric also directly correspond to an increase in O2 consumption as they oxidize the DOC into CO2.
But bacteria play minor roles in planted tanks, the main player is the plants as far as N is concerned.

Algae and plants are not Carbon, DOC limited. They might be CO2 limited.
Adding a different C ratio of food, eg, high Carbonhydrates migth help the bacteria population grow, that might help NH4 removal, but plants are much better in general at removal of NH4.

But a good bacterial colony is a good backup should you neglect your plant's needs, but so is a decent filter:) I do not think the role of bacteria and Carbon is significant as you contend and you have not offered any compelling evidence to suggest otherwise in the research nor observational.

@tom said:
The second step is in reducing our filtermaterial.
Biofilms in filters take up huge amouts of nitrates and TE's for there metabolism.
So how much TE and NO3 do aerobic bacteria in the filters are use up?
Please tell me how a filter that is aerboic with redox values at 350-500mv is able to reduce NO3 to N2 gas?The denitrifiyers neeed a range of redox values around 200-300mv This may occur in the substrate, but not in the filter in any significant way. This is easily testable by an aquarist with a good set of kits.
See how much NO3 is removed by removing the plants and letting the filter remove it.

I think you will quickly see that it doesn't do much:)
This is common sense, not technical science.

@tom said:
So we got ride of all filtermaterial and simply use them for only heating, co2 addition and water flow.
However some plants simply will not grow if there are no nitrates.
So you'll have to add a fluid-sand-filter for this purpuse.
FSF are poor filters IME and IMO.If they stop running for 15 minutes or more, their colonies die off fast. Also, adding filtration only changes the NH4 to NO3, you first need to have NH4 to begin with, in planted tanks I have not measured any NH4, it's used up by the plants as fast as it's produced.

We have done some tracer enrichment studies with N15 and I plan on doing some here at UC Davis with radioactive N rather than mass spect type work.

@tom said:
The only element that can't be found in this fishfood is Potassium so
that's all you need to add extra.

All basic rules for a planted aquarium still have to followed.
So you will still have to add co2, plenty of light, regular
water changes and have a low KH.
Why a low KH? I do great at high KH's, research both in natural systrems and in lab studies show plants do better in higher KH's. There are relatively few exceptions(1% of the commonly kept aquatic species), but even those will grow.
Also, water changes: thius removes N and C each time, therefore the role of the bacteria is GREATLY reduced in decomposition's role.

Your exporting all the C and N from this system which was your original premise. This nulls your entire argument.

@tom said:
Most research into this stuff has been done by leading dutch biochemist Adriaan Briene.
Before this he also studied the Redfield ratio ( N - P ratio )
His pages are in dutch but can be found here.
and here

Give it a try, and you'll see some amazing results.

Okay, this guy, I keep hearing this Redfield ratio pop up from the Dutch sites.
There is a problem with this concept and notion and I've argued it into the ground several times with no real response back that had any merit.

Redfield ratio deals with nutrient limited open ocean phytoplankton. Aquatic plants are radically different and totally different in terms of a niche. They also possess different ratios, roughly7 10: N:p ratios, FW algae, about 14:1 on average if you review the relevant research on specific FW plants and algae. I've done that.

The other issue with the Buddy ratio and that whole mess: it assume you can limit the algae through ratios and such, those references are for marine phytoplankton algae, not FW systems. The other issues: aquatic plants and small algae are not even in the same niche and therefore do not compete for the same resources, even if they use the same things such as N, the scale at which they become limiting are enormously different.

It's like suggesting mice and elephants are in the same ecological niche, again common sense says otherwise.

Science is useful, how you apply it and accept it is another matter.

Bringing up the DOC issue is good, we had suggested adding glucose to the water to amplify the bacterial growth as this is gone in research for studies on carbon bacteria limitations. We discussed this years ago on the APD in more detail as it applied to planted tank, Neithe rI nor Roger Miller found an effect.

I have a hard time seeing that it would for the reasons stated here as I have not been able to show that is did anything on a more practical and controlled manner for planted tanks.

Then the food source does not matter and this allows you independent control of things like C and N and K etc in a planted tank or a wetland or a growth chamber etc.

My critque here is not personal, but the arguements present do not make much sense based on the research and the application. To the average aquarsit without a background in biogeochemistry of wetlands, they might certainly seem convincing though:)

But it's specificaly what I do for a career and hobby, not many are that lucky.

If you are inteersted in knowing more about DOC/POC and carbon's role, and a ton of references on this subject, I will have an article coming out on the www.BarrReport covering Carbon in great detail.

This(carbon) is the core of biogeochemistry in wetland soils and is heavily studied in the USA in Florida.

Tom Barr

2,069 Posts
@tom said:
>> Food in, plant growth out. <<

This way is still growth limited by the amount of TE's that comes from the food.
Depends on the plant's growtrh rates, if limited with low light, no CO2 additions, it can supply the needed nutrient demands for months, years even.
Substrate sources can provide this since the amounts of TE are very small, while a nutrient like NO3 is very large and the substrate source might run out after a month.
Fish waste alone cannot supply a high light tank with CO2 and dense plantings.
You'll get algae due to NH4 not being cycled fasted enough=> leads to algae blooms.

You can test that fairly easily.

Many tanks run that way, and I don't feel the need for speed.
I think the proper question is how fast do you wish to grow the plants?
I use 3 basic groupings: Slow, medium and fast.

Slow: non CO2, low maintenance, nio water changes, general neglect, tanks look quite good, fish health is good, the plant health is not 100%, but that's not the goal here, decent looking tanks can and are acheived, it requires patience.
Medium: Low light still, but with rich CO2.
Dosing/water changes are done weekly, slower gerowth, easy to grow any plant, light slows the growth rates down, thus the uptake, there is a lot of wiggle room with routines and dosing here since the uptake is slowed down and the plants do not suffer right away.
Good for most folks over the long term.
High light: great for gardeners and scapers wanting to have dense growth and to prune and grow plants fast.

Comparing this, with your EI / armano style of planted tank running is useless.
No, not really, Amano and myself use both high and low light approaches and use them effectively to reduce dosing and pruning issues.
Many Europeans use less light than folks in NA. That allows more wiggle room with differnt dosing routines.

When you add more light, you quickly find that many of the routine that worked at lower light, now give you trouble.

Reliance on fish food declines as you add more and more light and you must add inorganic forms of N, such as KNO3, as NH4 forms will cause algal blooms.
NO3 is far more benign than NH4.
As loing as the NH4 is maintained at very low levels(in = out) things work well and for the same reason reagding algae control and plant health.

If you unbalance these, you will get algae or plant deficicency issues.
That's the balanced part:)

It's all about rate and what rate you desire for your given goal and routine and habits.

The Amano style and the EI both work at high abnd low light ans can still be done well at any of these lighting/methods, even non CO2.

I've done 2 non CO2 planted tanks with no fish.
It was fairly easy to maintain nutrient level at very low dosings 2x a week using inorganic nutrients. I did water changes once every 3-4 months after a pruning.

Simple thinking by me : light W/gal x 10 = co2 level

The point is to decompose N, C and P by using the right c:n ratio without losing it to sediment or filter uptake by
regulating the amounts of heterotrophic and nitrifying bacteria.
Removing a biological section of the filter means you simply allow more NH4 to use used rather than having it convert to NO3........the amount of N is still the same.......the bacteria population only regulate the FORM of N, not the export/import.......... the amounts of C used by the bacteria from food is rather small in the overall CO2 demand and import/export of CO2 with the air above.

In highly productive areas where there is a large amount of organic material accumulation occuring, like a nasty swamp, then a fair amount of CO2 can come from these sediments, but our tanks are not very rich by comparison.

You need to be specific with this, all I get is a listing or journals. Therer are many denitrying studies done on wetlands and bogs.
Do these apply to your tanks? Do we weed and add fish food to these natural systems? What are the organic matter loading rates in these systems?
The OM loading rates are much higher than our tanks.

This is easily testable.......
Remove the plants, add only NO3 as a source.......see how much is removed, the amount without the plants removed will be lower since the plants pump O2 in the substrate and reduces the denitritying bacterial regions.

Measure how much loss of NO3 you obtain over a week's time, then add the plants back and allow them a couple of week to grow in and measure this difference.

The NO3 removal is very low relative to the plant's uptake.
That also does not include the NH4 removal plants also do.

I know wetland denification is well explained in Aquapalnta and Reef Art. I made a detailed diagram of all of the N cycling processes that occur in a submersed wetland soil.

Wetlands can become Carbon limited in some cases: Reddy, White have done a fair amount of research on this issue. See this thread for more on C:N issues and food. Many reef folks limit their food way down.

The FSF is used for it's thin biofilms and creating the still needed no2.
Filters are never to be stopped..
Yes, but with routine pruning, these films are minimized, with good plant, they are also minimized as well. Algae and other eipihytes also form in these thin film spaces.

Water changes ( 25% / 2 weeks RO water ) is done only to prevent inhibition / toxicity.
Okay, like what might be toxic or inhibit what specific level of something is required for this to occur??
I've gone years without a water change, I have friends, that have 2-3 years without one.............N is breed etc............
Again, it gets back to rate, the faster youm go, the more issues you will have with things running out nutrients, rather thann toxic effects from build up.
Espeically when all you rely on is food alone.

You can rely a fair amount on food with low light, but topping it off with some inorganic macros will improve the plant's health and make the tank look better. Balancing food for the plant's health is not perfect, there are trade offs..............

Plants will also have that effect.
What effect? Allelopathic? I don't think so, this is easy to test we go again...........
Add carbon, carbon will remove any allelopathic compound, this is the standard control for aalelopathic compunds done in research.
Additionally, allelopathy has never been shown in the field in any aquatic plant on algae or another plants ever to date.............
Additonally, allelopathic compound produced by all 300 or so aquatic plants species all produce the same effect and the same intensity on algae?
What are th eodds of this ocurring?
I'll tell, you none. Well perhaps a few trillion to one:)

Ca release from the food also increases the kh slowly. ( Low Kh )
Ca will also bind to P and Fe ..
The Ca released from food goes right to the plant. Ca will not raise KH, KH is HCO3, in planted tank without water chnages and CO2 additions, the KH goes down due to bicarbonate usage when the tank becomes CO2 limited.
Ca will bind to PO4 and but to Fe? PO4 ansd Fe will bind....but I'm not sure how you plan on binding Fe3+ to Ca2+.
In any event, they(Ca and PO4 or PO4 and Fe) can form in the oxidized water column, then be reduced into their ions in the substrate or by the roots themselves, plants and the substrate are not static, the nutrients do get cycled.

The redfield ratio has been debated since release on many forums.
That conclusion is incorrect and heThe guy who has the site) would have a difficult time backing it up for FW applications. The reasoning is flawed and the application is wrong. It's not a marine phytoplankton nutrient limited system. It compares apples to oranges. You can try to do that, but I do not agree with that illogical conclusion.

It also does not make sense in practical terms, I've done the opposite of some of those same conclusions and had quite the opposite effect.
I had excellent plant growth, not algae. I can repeat those experiments and so can(have) others(for many years).

2,069 Posts
Problems lie in the P factor, it often forms ion-bindings that won't show up.
The total nutrient flows are more importend.
I've discussed SRP and DOP and DIP at lengths on the APD and elsewhere.
Total PO4 test will measure this fraction, it will not measure preciptated FePO4 for example.
But we have 1-2ppm of PO4 coming from an inorganic source: KH2PO4, this is inorganic SRP PO4. This is the plant biolavailable form, algae can use organic forms of PO4, the sediment will have PO4 accumulation in the form of precipitate, but this has limits before this begins leeching out in the reducing layers o the substrate and re enters the water column in bioavailable forms.

I dose PO4 regularly, many do.
You can measure it via no plants and with plants for a control as far what fraction is removed by the plants themselves.

You can also see the plant's response to addition of PO4 as a dramatic increase in plant production.

Any one can do this and see it for themselves.
I suggest you do the same. Then you'll know.

I'm interested in the R&D that you have been doing on algea conditions and
the NH+ levels, did you put any detailed info on the net about that ?
Just started with your site ?
Over the years I've written volumous amounts of information about my findings starting about 10 years ago, 8 years ago on the web.
I knwo what cause algae species specific growth, I can culture these algae and then test the responses. Then repeat it and see what other folks have found.

I'm also one of the people that's isn't affraid of watching tanks get filled with algea.
The more we learn , the beter we can help others.
I'm still young in that way.

Well, you will be scratching your head now if you try some of these methods I've suggested. They will run counter to what you have learned thus far from the sounds of it.

A lot of research into this method still has to be done, as you sad, before all factors and underlying mechanisms are clear.
Comparing a planted tank to a huge natural ecosystem is also useless.
We simply don't have the facilities and capabilities that you have.
I can do that because I work with both, they are much more similar than people suspect and all the methods various people use and suggest work are also very similar.

This notion bothers some people, but the idea is quite simple.
It's all about balance, what aspect of balance? The rate of growth for the plants.

I've tried more methods than perhaps anyone, I kept trying them till I have done all the main ones out there and then went back to understand and test them further. I'm still working on the marine tanks and the success there means much better algae control apporachjes for the reef folks, something they have a very rough and expensives time dealing with, makes our issues seem benign and easy to deal with.
I'm pleased with that progress as are many Marine folks I've done presentations for on algae in their systems.

Try using wodka as a form of C that'll do the job ..
Not all researcher found liniearity between labile and stabile doc and denitrification. Good luck with your new job ..
Yes, that would work fine. I have ETOH and use this for a number of things, mainly Chl a extractions.

Try this: add CO2 to 30ppm, keep it there during the photoperoid.
Add KNO3 at 1/4 teaspoon per 2 5gal 2-3 x a week
Add TE at 5mls 2-3x a week(opposite days to avoid Fe/PO4 interactions).
Then add KH2PO4, abut 1/16" teaspoon(divide the 1/4 or 1/8" into 4 or 2 equal parts for 1/16") 2-3x a week the same days you add the KNO3.

Do weekly 50% water changes with tap water.

Tell me what you see.

You add what the plants need, not worry about the algae. The goal andf fcous is growing plants, not killing algae, that is not why any one got into this hobby, they became interested in growing and nice planted tank.

So stick with that original question, "how to grow plants?"

Other things can side track you.

Tom Barr
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