[plantbrain]

Originally Posted by naman

“Nine common species of aquatic macrophytes took all their phosphorus from the sediments when grown in situ in both a mesotrophic and a mildly eutrophic bay. Even under hypertrophic conditions, the sediments contributed an average of 72 percent of all the phosphorus taken up during growth. These experiments unambiguously demonstrate for the first time that submergent macrophytes in nature over-whelmingly depend on the sediments for their phosphorus supply and characterize them as potential nutrient pumps to the open water.”. (Phosphorus Sources for Aquatic Weeds: Water or Sediments?; Department of Biology, McGill University, Montréal, Québec, Canada H3A 1B1 Phosphorus Sources for Aquatic Weeds: Water or Sediments? -- CARIGNAN and KALFF 207 (4434): 987 -- Science)

It says, for these species, that they take PO4 from the sediments an average of 72%, but the error bars are large. It just says depends on sediments, they can and will go either way, which other research implies.
suppose the sediment had little PO4? What then?

So since you are focused in natural systems, is the aquarium even remotely like natural systems?

Light?
CO2?

In natural waters (as tropical forest’s rivers) we see VERY low PO4 levels, and very rich sediments. Almost everywhere where plants grow (exept weeds as Elodea).
So, which method of fertilizing is more “natural” and closer to natural ecosistems ?

More "Natural" does not imply better horticulture.
Horticulture has it's own unique ecology.
You mention bad science yet you make very basic mistakes in your own logic.

BTW, here's Elodea, the species specifically in question is an apline Stream at 7200ft , there's no PO4 at all in this water, good CO2 though.



Growing pretty good there and is most of the alpine lakes in the mountains here in CA BTW, the water is snow melt in a granitic aquifer. Pretty clean water.

Is it more beneficial to have good microogranisms cultures (rotifers, microbes etc) in rich and loose substrate (as ADA’s) to let them recycle wastes in sediments giving nurtients for plants and do not syphon gravel regulartly killing their environment ?

I agree with more biota in the sediment, but at some point, the sediment accumulates too much organic matter and needs to be cleaned out, /vacuumed and the stems need uprooted and replanted.
A good water change and trim helps and things get back to normal.
You also do say 1/4 of the tank at a time so the system is not disturbed too much. Doing the entire sediment is not a good idea.

Is it more beneficial for aquarist to have less PO4 in water column to have less algae during disbalance (as we know PO4 itself is not the “cause” of algae bloom – pure plants growth is) and feed plants mostly from substrate?

This assumes another variable, not directly PO4.
PO4 alone in a control tank will not induce algae.
Also, the concentrations are ridiculously low to limit algae.
Plants, as the research you cited above mention, add PO4 via leakage from the sediment to the water column, plenty for the algae to grow, at least the species of algae that concern us.

That's why PO4 and sediment and macrophytes are a big research concern.
They act like pipes, pumping O2 to the sediments and releasing N and P into the water column. When they die back in the winter, they rot and release a lot back into the water column in natural systems that in the north/alpine systems, in tropical and subtropical, this does not occur much, but growth typically is reduced due to reduce light, the same is true for algae.

If you mess up CO2 or add too much light, or do not dose something.....well, yes, but that's not due to PO4 limitation, nor will PO4 limitation save you any more than not doing it in aquariums.

Folks have noted this for 15 years.
This is not some new thing.

You seem to suggest that if we make a mistake somewhere else, then the PO4 limitation will somehow save us from algae, yet I see no evidence for this, nor do other folks, I have plenty of nice examples of aquariums to show this.

Near as I can tell, I've never once seen a tank that you have ever done.
Ironically convenient.....I have less algae issues, grow plants faster, larger etc than the ADA vendors here do.
I know them personally and bring plants to them.

Guess by yourself… but do not forget to look at Amano’s tanks and tanks of those falks hwo use ADA’s system/method/approach/routing, especially of those who had never read this or that forums

Oh sweet irony...........I need pop corn for this.

DO WE NEED TO CARE OF HOW TO FEED PLANTS – FROM WATER COLUMN OR SEDIMENTS?
Not at all, as they grow in both cases well*… but only UNTIL we don't think about Stability and Usability of the method which we choose to maintaine our artificial environment - planted tank.

I actually do agree with you here.
I support using both the sediment and the water column, you suggest that we add very little or next to nothing there.

*If it is known that stem plants have no negative effect on growth rates being placed in environment with low nutrient levels in water column but with rich substrate, AND that root feeders will be unhealthy without rich substrate.
Than, wich nutrients location should we prefer!? Ha!?
Not to mention the Maintenance factor.

Both, not one or the other.
Sediment ferts are certainly easier.......and at lower light levels, this relationship will improve.

Something I've been saying for no less than 15 years, mostly upon death ears sadly(not yours- but many other folks).

**Moreover, P is not the factor of Stability, as CO2 uptake greatly depends on Rubisco activity, which is directly depends on N avalability first and for most, not P at all.
BTW plants can keep spare P orders more than N.

True.

“Emergent macrophytes respond positively to eutrophication, but fertilization experiments have shown that nitrogen rather than phosphorus may be the key element. Submerged macrophytes are adversely affected by a large increase in the external phosphorus input to a lake. This effect may be caused by epiphyte shading, phytoplankton shading or deposition of unfavourable sediments.”. (Influence of aquatic macrophytes on phosphorus cycling in lakes SpringerLink - Journal Article )

They have gone back and forth for decades on this, I'd suggest looking at UF's IFAS Aquatic Sciences dept.
Bachmann and the role of plants and the algae have been really thoroughly investigated. The above is one lake, they did 300+ lakes...........

You can say something about that one lake and within it, but you cannot generalize too much beyond that one lake. With 300+ different lakes, now you can look at general patterns.

These are also tropical/subtropical lakes with plants or at least some access to them, they are shallow, never freeze over etc, much like our tanks. Lots more light etc, less CO2, but still, if you want to use a paper, cite a good one.

Caring of CO2 without proper NO3:PO4 ratio is pretty much usless.
1:10-16 (Redfield ratio) is good rool of thumb (Seachem, PPS-pro), not 1:5 as in EI. Lack of P lowers growth rates 2-3 times, lack of N leads to lack of C and drops growth by 5-7 times vertually stopping it and hardly exceeds the saturation level (= survival edge) of photosynthesys. (see Oles data SIL_poster_2004.pdf http://www.bio-web.dk/op/pdf/SIL_poster_2004.pdf )

You assume that N is limiting.
It can go either way here.
P or N, and we see this in natural systems and can see it in our tanks.
I nor anyone suggests running N or strongly limiting concentrations.
This is not logic, this is a bad assumption(neglecting the tank).
I can say all sorts of things to support a better method if neglect is really the driving issue you seem to imply.

We should all use non CO2 methods if that really is the argument

Any nutrients fluctuations lead to pure plants growth = algae.
Substrate IS much better source of nutrients for plants becouse it is more stable source than water column (that human factor), so when we have a substrate based system like ADA’a there is no radical slowering of growth rates = less algae when we lack of something in water column – plants just take what they need and when they need (mostly) from substrate.

I agree sort of except for the parts about algae, and the part of this either or business(sediment or the water column). I've long said both, not one vs the other for fertilization. I've never come against sediment fertilization and have supported it's use and still do. Unless you know specifically how to grow algae, you really do not know why and what causes it.

I also totally disagree with the nutrient flux = algae.

What's the difference if I go from say 0.5ppm of PO4 to 5ppm PO4?
Is algae limited in any way in either case?

No, not at all.

It helps to grasp how is it possible to do not fertilize water column at all and have a lush stem plants which love PO4. This effect is known long time ago from earthworm castings/garden soil “method”.

It is possible, no one disputes that Naman.
What is real the issue is that you seem hellbent on this one vs the other method instead of seeing that both methods work even better than any one of them alone.

Synergistic methods used together, along with good routine care(so that things do not become limiting, or that you really mess things up, proper lighting(something most any method should and does address) CO2 etc), these are not things that ADA alone suggested.

EI and other methods all pay some credence to them, you take this very narrow interpretation that it's just nutrient water column dosing and nothing more.

Clearly anyone can look the methods up and see for themselves that they all do, most any how to grow aquatic plant site does.

but ADA’s method differs not only with this, but with lighting method (gradually rising intensity changes a lot of things for plants!), filtration, water circulation, co2 delivery method, etc… and maintanance routings which evolve from all of this.

Most any site tells you this Naman, this one(ASW, APC, BR, TPT etc) or any other.

This is not ADA and some miracle of Amano's........

It is much more than merely “EI + Aqua Soil”, so this label or “PPS-pro + Aqua Soil” will never stick to it with someones “inventor’s” name except ADA’s, I hope.
I am not surprised that this “inventors” even have no clue why ADA’s system works so well...

Amano sells what he knows and does. It's easier to sell what is the prevailing market than the suggest something new. When ADA started selling AS and other products, the idea that you could limited algae by adding ferts to the sediments was wildly popular.

He's sort of stuck a bit with it and has since.
But the good part is that he suggests lower light, and if you do use high light, only a couple of hours. If you drive light at 500 mic/mols/m^2/sec for 12 hours, this will not work. Plants will run out and not be able to maintain such high rates of growth.

This is not typical for most aquarist.
So why does he suggest adding ferts at all to the water column and how do reconcile the fact that plants pump and release PO4 into the water column?

He runs the tank at a lower growth rate using less light, he's trying to hit the market and still give folks good results. I can and have done this, many have. That's not new either. Still, plenty of folks have nasty algae and issues using ADA, some many will not listen, but my advice and Amano's are not that different, nor that of Ole's, Troels, Karen Randall, or others. We say it in a different way, we each have a different background and area that we are better versed at, but we really seldom discuss plants when we get together.....


It's the hobbyists that make a big stink about the perceived differences, not us. That topic we are certainly in agreement on(and it was discussed at the AGA conference not long ago).

Use less light, no matter what method you use, the results will more stable and less algae. The trade off is less growth rate. That's where it all starts.
We all know that. Then if you like the no water column ferts, knock your self out, but simply because it works for you under some conditions, does not imply it works or is the best method for everyone.

You really do seem to suggest that.

No one method will satisfy everyone's goals.
Some want more light, some less, some garden, some neglect their tanks.
You need to focus the method that best gets you to your goal(whatever it maybe).

Sit back and consider that before responding.
Ask the person you are helping what is their goal?

Regards,
Tom Barr