You have not supported your contentions, I have.

Eh?

References in science relevant to the topic. Examples in the hobby,
your own research etc. eg have you actually tried high PO4 in a
planted tank?
Add KH2PO4 etc......is it repeatable? Can we find many exmaples in
natural field studies as well?

Actually I have proven quite definitively that excess PO4 that is
available for both plants and algae equally, not not cause algal
blooms in planted tanks with good plant biomass, CO2, moderate-high
light, good dosing of the other nutrients.

Anecdotal. If I can limit via P (in the world where 0 means
0), or I can limit via Fe (also in world where 0 means 0),
or I can limit via "Factor X", then...

If I choose P, and you choose "Factor X" (knowingly, or
not), then by your science, you can "prove" P is "wrong" all
day long.

No, I ve measured PO4 uptake due directly to plants, not algae or
complexing, precipitation.
Why would plants remove it(some can be due to luxury uptake), there's
plenty for the algae to assimilate as well and yet there is no algae
biomass?

This is the observation and has been repeated for many years
now(Tropica, Oriential Aquarium amongst other growers of plants and
Florida has a huge aquatic plant industry and is where I live).
You can pick NO3, Fe, K+ etc, there's plenty for the algae and the
plants.

By limiting these nutrients, you select more for the algae than the
plants which have much larger nutrient requirements than algae.
Algae live in a much smaller environment and difference niches than
macrophytes.


If you want to talk about causual mechanisms, you need to be able to
isolate the issues and deal with PO4 in a controlled manner.

No, you have to deal with BGA in a controlled manner. PO4,
in science-pure water, won't support any form of life, at
all. You simply cannot control for P, alone, in the life
cycle of BGA.

I was not talking about just water and PO4.
I mentioned to control the other parameters, CO2, light, K+ etc and
vary just the PO4 alone.

Folks often have trouble doing this, they then blame the wrong
parameter such as PO4 rather than low CO2 near the end of the day or
low NO3 etc.
A chemostat does this but is tricky to use and get set up correctly.
Many pelagic algal studies use such a device.

Aquarist can do something close that will control reasonably well for
PO4 by knowing what their tap water(or RO water) contains and doing
large frequent water changes and dosing afterwards to maintain good
nutrients levels while varying the PO4.

Large frequent water changes keeps the nutrients from becoming too
highand the frequent dosing keep the nutrients from running out. In
this manner you can vary whatever nutrient you want to consider.

Many have done this and found this to be true with high PO4 levels up
to 2.0ppm.
Surely at 2.0ppm the algae are not limited, so something else is
keeping the algae at bay in planted tanks.

I suggested a number of papers to support this observation.
You might want to read these before coming back with nothing more than
banther and your own anecdotal comments.

Then you would have something to discuss about why lakes and rivers
with plants are clear and algal free and aquariums that also have high
PO4 levels.

You can argue that lakes are not like aquariums yet what you based
your studies on are also based on Northern lakes often with no/few
macrophytes relative to the lake's surface area.

If you have studies showing planted tanks produce more algae with
added PO4 vs limited PO4, please, let's see these studies or show some
data of some sort.

I found that the Chl a concentrations decreased in well planted tanks
with PO4 levels at 0.5-1.0ppm range over 4 weeks using glass slide
substrates(ref:EPA protocols) while plant biommass increased
dramtically. A tank control with PO4 limitation at less than 0.1 ppm
PO4 had 40% less plant biomass and increased algae(62% more algae vs
the PO4 enriched tank). Plant uptake was estimated at 0.3ppm per day
uptake in the high plant tank.

So what have you found?
I've reported the uptake rates in planted tanks for sometime
concerning PO4 and NO3 etc.

Regardless of lighting levels? You sure you want to say that?

Absolutely. I've never, ever, reduced lighting on the reef
tank.

So less light also? This is a plant list and I'll keep it confirmed to
this topic, reefs are not = to plants, they are critters, some have
algae, many don't. They can supply a great deal of their N and P from
the food they catch rather water column inorganic nutrient uptake.

Big difference. Now if you want to talk about a macroalgae/seagrass
bed in shallow water such as the Keys, things might be closer to being
a comparison.

Uhm, I did in the last post, I gave multiple plausible causes.

I reread, closely. Mostly "ain't it". Maybe I missed your
causes for your style.


Pruning, this removes the algae on the lower leaves.
Water changes, removes any algae scrubbed off from glass etc.
Fluffing plants and good current, remove a fair amount of
periphyton(See Zimba and Hopson)
Photorespiration in specific species of algae(Bowes, Madsen)
Light competition( also Bowes)
Algae sensing a good environment to grow(low Dissolved O2(microsites),
NH4)
Algae and macrophytes are in different Niches( Sand Jensen paper)

I did not see a single reference of any kind from you.

Still haven't except for Paul and Kevin anecdotal paper.

You can believe want you want, you are still wrong.
Research shows this, I can show this in a plant tank, you can show
this to yourself in a planted tank.

Anecdotal, and the lake study is ill controlled.

So someone that has not read the research and has not tried it, bases
their own contentions of anecdotal study by Paul/Kevin knows all about
it then?

Okayyyyyyy whatever

The AGA contest winners, all the plant clubs have got it all wrong and
you are the only that's right?

Anecdotal.

Is a large pattern and highly experienced group all wrong?
If I can achieve high levels of health and growth with high PO4, and
is repeatable with many other people incorrect and we are assuming too
much here?
Why are some lakes also similar with similar observations?
I guess they are all wrong and you are right?

If I were you, I'd be questioning my arguements.

Humm you might want to actually try it and see about this, maybe read
some of the references, ask around.

I live it.

So do I, but.......I also try different things such as adding NH4, PO4
etc and control the other parameters, I cite and support my arguements
and these also support the observations. You?

I limit P, provide high-light, dose PMDD, and
have very few problems with BGA/Algae. My plants out pace my
eagerness to prune, I surely care not to "improve" their
status any further.

Let's have something to compare it against.

You apparently only know PO4 limited systems, if by adding PO4 to this
system, you see an improvement with aquatic plants and no algae or
less algae, what would you think then?

What types of PO4 levels are we talking about here?

In order to limit BGA/algae growth, you need to get below 0.005ppm of
PO4, see Ulrich's paper among others.

This has been my contention all along, the needs of the plants are
larger than that of the algae.

N:P ratios for aquatic macrophytes are around 10:1 and for FW algae
about 14:1.
Adding PO4 will favor the plants when both are present rather than
limiting it.

Like I've been saying, try it out since you don't believe me, I've
tried the PO4 limited approaches in the past also. I know both sides
of this coin.

Since you seem concerned about empirical data, I've given a large
number of papers to peruse on aquatic plant and algae ecology and
physiology, have done my own research and given some actual data
yet........you've provided none to support your own "anecdotal"
arguement.

If you want to ask for citations fine, but if you do not read them,
don't ask for more

Regards,
Tom Barr