Nitrate/Phosphate experiment.

[plantbrain]

I have never understood how a tank with healthy plants in nutrient laden water can have far less algae than a tank with zero nutrients in the water column. This is at the same time both true yet counterintuitive. Then I came across an article on plant allelopathy.
This concerns the process by which plants release chemicals that either benefit or inhibit the growth of their neighbors. Perhaps our healthy plants are somehow producing and releasing their own form of algaecide.

If you add active carbon or do large water change= no allelopathic chemicals, thus there's the control. See any evidence that using activeated carbon or doign large water changes somehow...induces algae blooms?

I, nor anyone else would suggest it does

So this is a very easy test many have already long done for well, decades......so that's been falsified, scratch that off the list. Research is very weak that it does have any effect with real whole live living plants.

Not ground up extracts...

Something will grow there.
Plants and algae can tell if someone else is "already there" growing.
So the algae can wait and germinate when the plants stop growing and start to die back, releasing nutrients BACK INTO THE SYSTEM AND ROT AND ALLOW THE LIGHT TO COME IN.

So poor/weak growth, + high light = algae, at least in natural systems.
If you remove all the plants, well, then you will get algae once again, as well.

It might be just a simple thing, algae do best when the plants are not.
So they(spores) wait.

Plants are mostly clonal in aquatic systems or buds etc.........so they do not have seeds typically for seasonal changes in permanent aquatic systems. They do not need them much.
Algae do need sexual stages to survive in most cases and compete.

Why do certain algae grow?
I mean do not algae compete amongst themselves?
Plants?

Why don't we have 10,000 species of algae then if it's all about nutrients?
This makes a weak argument, without some understanding of ecology, life histories and niches they occupy.

Same for plants.

Regards,
Tom Barr

 

[plantbrain]

Do you think you could be going from NO3 limited, to PO4 limited situations?

Sounds like it.

So do you think plants are better able to adapt to low PO4, or a more critical nutrient like N?

N limitation will retard growth a lot more than P limitation.
There's a great deal of evidence for this.

Thus most subscribing to limiting one single nutrient, have historically chosen PO4. This can be used to slow the rates of plants growth.

This can also reduce the demand for other nutrients, like N, and also CO2........

If N and CO2 and well supplied in both a limited and a non limited PO4, then we a dramatic increase in growth. In N and CO2 are not adjusted and become limiting, then you will see algae and poor plant growth with non limiting PO4 dosing.

Both of these cases refer back to Liebig's law of the Minimum.
Unless an experiment has a control where it's 100% or close that the N and CO2 are non limiting in both cases, little can be concluded from such test.

Having done this, as well as many others who have used EI etc.......we can assure you, it's not the nutrients.

It might be due to poor CO2, poor NO3, but these can both be addressed and adjusted to see. This looks at the other possible causes, not just assuming that PO4 defines the system in and of itself.

This is a far more logical and safer approach. This way you have looked at all the possible issues, not just assuming one is correct and there's no indirect causes, even though there's strong evidence otherwise.

Otherwise, you leave yourself open.

Regards,
Tom Barr

 

[The Plantman]

Do you think you could be going from NO3 limited, to PO4 limited situations?

Sounds like it.

Yes, this is what I think from my own experience. Limiting NO3 is not good.

So do you think plants are better able to adapt to low PO4, or a more critical nutrient like N?

I think that they can adapt better to low PO4, yes.

N limitation will retard growth a lot more than P limitation.
There's a great deal of evidence for this.

As I have discovered for myself yes. I do not know how plants use nutients or what is more important to them, besides NO3 and PO4 are two important ones. This is why I am trying to discover for myself. I cannot take someones word for it. No matter who they are. I must discover for myself.



Tom, thanks for your wisdom once again.

I noticed the algae bloom 3 or 4 days (I can’t remember) after using Tropica with N and P. I’m trying to get the tank back to where it was. Once the algae is 95% gone, which I’m already almost there (I did two 20% water changes and added Tropica without N and P). The algae are already dying off. I think I must have fantastic tap water for growing plants!

I am one of those guys that just have to “find out for myself”. I’m going to try upping the dosage of Tropica Aquacare without N and P and up the fish load slightly. I had a feeling that Limited PO4 would cause less algae then limited NO3, I think I've proven it to myself and you have helped me confirm that that is true.

Once I am almost positive that PO4 is the only nutrient that is lacking I’ll try adding it again. I did do another PO4 test and the levels have already dropped below what the store bought test kit can register.

 

[The Plantman]

Plantbrain, would you agree that a planted tank given the right amount of excess nutrients but slightly limiting PO4 would still result in a "mostly" algae fee tank? yes, no?



But you would say adding more PO4 as long as all other nutrients are available you will still get an algae free aquarium only with accelerated growth? Yes?


Thanks,
Shawn

 

[plantbrain]

Plantbrain, would you agree that a planted tank given the right amount of excess nutrients but slightly limiting PO4 would still result in a "mostly" algae fee tank? yes, no?



But you would say adding more PO4 as long as all other nutrients are available you will still get an algae free aquarium only with accelerated growth? Yes?


Thanks,
Shawn

Well, minus green spot algae, PO4 limited tanks run pretty good IME.
But, why limit PO4 to reduce the rates of growth?

This really gets at the core issue, how best to management the growth RATES of plants, this is less about algae.........

With less light, then I have little issues managing CO2, and NO3, and also......PO4.

So all nutrient/CO2 management is easier, rates of algae growth are also slower.

Example 1 above.

Now, example 2 below:
If I say chose, high light + rich nutrients except for say PO4, the rates of plant growth would be less/reduced since PO4 is the bottle neck. But, I'd be wasting my light and electricity bill. Now you have excess/wasted light. Algae are still not limited...and now also have plenty of light.

Ex 2 is much less stable than Ex 1 low light + good CO2/nutrients.

It's also much less efficient.

I can also control rates of growth over a much wider range and much easier and more predictably with light than you can with PO4. Basically, I have a nice gas pedal to grow plants at any speed I desire, you cannot say this for PO4 limitation, it's much more unstable in terms of rates of growth and dosing etc.

This is about the rates of growth of plants, not algae.
Algae appears due to a CO2 issue/low nutrients/too much light except for perhaps PO4 but there's a lot of GSA in such tanks over time.

Since you limit plant growth with PO4, you also limit the CO2 demand.
With what I suggest, I only limit growth by light. This does not affect CO2/nutrients, it actually makes management of those even easier, and fully maximizes light use efficiency.

So algae has the least amount of light to grow, and the plants have everything they need.

I can grow more species, better, using this than wasting 2x the light watts with the same bulbs. I've measured this using O2 ppm as a metric for growth in real planted tanks, I had 110% with high light + strong PO4 limitation, 130% when I used 1/2 the light, but non limiting PO4.

This was the average for the 10 hour light period measured hourly.
This is a fairly significant difference in growth rates.

So you can get more growth using less light.
Not a bad deal.

The key is that less light= less CO2 uptake/demand also.
This makes 90% of the issues folks often have, go away.

Then nutrients/dosing is much less touchy.
You cannot take the light/CO2 away from the nutrients in all this.
I treat CO2 as a nutrient, and critical key one at that.

I would suggest you limit everything but PO4, then dose and pulse KH2PO4.
Wait, watch.

Then make sure you have more CO2, and get the gas tank!!!
Then see as you slow and progressively increase the CO2 rates/ppm.

You should figure a lot out going this route.




Regards,
Tom Barr

 

[The Plantman]

Well, minus green spot algae, PO4 limited tanks run pretty good IME.
But, why limit PO4 to reduce the rates of growth?

This really gets at the core issue, how best to management the growth RATES of plants, this is less about algae.........

With less light, then I have little issues managing CO2, and NO3, and also......PO4.

So all nutrient/CO2 management is easier, rates of algae growth are also slower.

Example 1 above.

Now, example 2 below:
If I say chose, high light + rich nutrients except for say PO4, the rates of plant growth would be less/reduced since PO4 is the bottle neck. But, I'd be wasting my light and electricity bill. Now you have excess/wasted light. Algae are still not limited...and now also have plenty of light.

Ex 2 is much less stable than Ex 1 low light + good CO2/nutrients.

It's also much less efficient.

I can also control rates of growth over a much wider range and much easier and more predictably with light than you can with PO4. Basically, I have a nice gas pedal to grow plants at any speed I desire, you cannot say this for PO4 limitation, it's much more unstable in terms of rates of growth and dosing etc.

This is about the rates of growth of plants, not algae.
Algae appears due to a CO2 issue/low nutrients/too much light except for perhaps PO4 but there's a lot of GSA in such tanks over time.

Since you limit plant growth with PO4, you also limit the CO2 demand.
With what I suggest, I only limit growth by light. This does not affect CO2/nutrients, it actually makes management of those even easier, and fully maximizes light use efficiency.

So algae has the least amount of light to grow, and the plants have everything they need.

I can grow more species, better, using this than wasting 2x the light watts with the same bulbs. I've measured this using O2 ppm as a metric for growth in real planted tanks, I had 110% with high light + strong PO4 limitation, 130% when I used 1/2 the light, but non limiting PO4.

This was the average for the 10 hour light period measured hourly.
This is a fairly significant difference in growth rates.

So you can get more growth using less light.
Not a bad deal.

The key is that less light= less CO2 uptake/demand also.
This makes 90% of the issues folks often have, go away.

Then nutrients/dosing is much less touchy.
You cannot take the light/CO2 away from the nutrients in all this.
I treat CO2 as a nutrient, and critical key one at that.

I would suggest you limit everything but PO4, then dose and pulse KH2PO4.
Wait, watch.

Then make sure you have more CO2, and get the gas tank!!!
Then see as you slow and progressively increase the CO2 rates/ppm.

You should figure a lot out going this route.




Regards,
Tom Barr

Tom, we are on the same page. Using light as the limiting "Nutrient".

What watts per gallon of T-5 light would you suggest as "low light"? 1.7-1.8? To start with and then turn up.


Thanks,

Shawn

 

[The Plantman]

Excellent Tom! Thank you.

 

[tackful]

I'm still stuck on trying to understand why a planted tank with nutrient-rich water has far less algae than one without either. A shaky hypothesis: IF there is such a thing as a natural algacide secreted by plants, and IF it lurks in exactly the same place as living or dormant algae, then might water changes or carbon filtration reduce both concentrations equally, thereby leaving the balance bewtween the two essentially unchanged, although at lower concentrations?
Like so many on this forum, I would never think of questioning Mr. Barr. I am simply very curious as to the exact mechanism by which healthy plant growth defeats algae.

 

[plantbrain]

Well, if you have a tank like this:

I can easily adjust the light up or down and then measure the PAR with a meter(this takes 15 seconds). I also have 2 different light types, I have a HQI(I have not used it on this tank for 2 years) 150W MH, and a pair of 55W PC lights.

T5's are even better than the PC's.

So I can change the angle of light. I can change the color bulb types, or mix and match, I drop the light right over the tank or 24" above.
Many many options for light, and..........with a PAR meter, I can measure them in comparable units no matter what type of bulbs, brands, etc my set up might be.

Now many do not have open tops, but most want one though:thm:
So you can cut metal window screen and layer these to reduce the light intensity much like shade cloth.

Another thing some do, they drop the photoperoid down, say to 6-8 hour ranges vs say 10-12 if they have higher light. I like 9 with my 1.7-2w/gal ranges, but I also raise the lighting up some.

Now if you lack a PAR meter, no plans on ever borrowing, getting one etc, you can eyeball this and adjust based on the plant growth, ask others and try and estimate a starting point, reference frame and go from there, 1.7W t5 is a good starting point, even if the tank was 24" deep and the light was 8-10" above the water.

I think you will be surprised.
HLD is a rough thing to cure one's self of.
Most spend $$$ to provide the best high tech solution for their goals.
Unfortunately, if also one of the worse things they can do as a newbie.

Some go the other way, a T12 40W bulb on a 55 or a 30W 36" on a 55Gal tank. You can grow water sprite floating etc and some others certainly, even with this, but not a nice thicker tank etc and lots of species.

Still, from 1.7w/gal, you can adjust a few different ways from there, cutting the electric bill, making algae go away, nice manageable plant growth instead of weedy growth. All while being pretty easy.

And no testing except perhaps a little to fine tune something say like light, or test the tap to see what's in that etc.

In general, if something looks wrong, 50-80% water change followed by dosing, since this takes care of the nutrients, and the light does not change...........what's this leave us?

CO2/current, filter clogged etc.

Now you narrow the management issues down much faster.

I think most are really surprised that the tanks look so nice with lower light, few will argue that the algae is ever worse off with less light also.

This + say CO2 gas tanks, + ADA As, would make the results you have that much better. Then it's much more about gardening and aquascaping skills, which was likely your original goal?

Do not get side tracked from that.

Regards,
Tom Barr

 

[plantbrain]

I'm still stuck on trying to understand why a planted tank with nutrient-rich water has far less algae than one without either. A shaky hypothesis: IF there is such a thing as a natural algacide secreted by plants, and IF it lurks in exactly the same place as living or dormant algae, then might water changes or carbon filtration reduce both concentrations equally, thereby leaving the balance bewtween the two essentially unchanged, although at lower concentrations?
Like so many on this forum, I would never think of questioning Mr. Barr. I am simply very curious as to the exact mechanism by which healthy plant growth defeats algae.

Concentration is still part of the dose.
You should question everyone really.
Since dosage is concentration X time, and there's not much left and not much time for exposure.

Why does it have to be a chemical secreted by the plants?
Why does algae not grow in the winter in many lakes?
Temp?
Light?
Lack of a turnover?
Life history?

Does an alga need to grow all year long to complete it's life cycle?
How about annual plants?

Do other plants suppress them?

Algae can detect a good time to bloom by their own numbers, by the CO2 changes(a good indicator of ecological change in aquatic systems), decaying vegetation.......now think about this one.........what happens when a huge amount of organic matter comes into a lake, into a stream, turns up all this reduced sediment, adds lots of nutrients..........this is a good time to grow.

So they have adapted to only germinate then.
Evolution plays a role on when and how these things occurs.

If our plants suddenly are CO2 limited strongly, then........they will not do well, + they will leach chemicals, and not the good kind.

Our light is also pretty low compared to natural systems.
We keep things much more stable, but we also uproot from time to time and algae often appears if you move the plants around, prune too much, pull the roots up and then do not follow it soon with a water change etc.

There are likely multiple reasons for algae blooms, many fairly specific to each species.

Still, plants, not nutrients, define these systems, where present.
If no plants, then algae define these systems, and to a lesser degree, nutrients.

The question remains though, what causes algae, and what prevents it?
Simply not having this answer(complete or partial) does not imply the fact that we can rule out potential causes. Some seem to think they have the golden Fleece if they can control algae somewhat, but it does not imply anything as far as cause.

And if you say you do not know specifically or generally, what cures algae to someone's satisfaction, and some one else claims they know, then many go running off to try that.

I have the "cure for cancer", no.........this is a pipe dream.
Stick with good plant growth.

The same is true for crops vs weeds.
With good crop management and rapid growth, most crops easily dominate the weeds.

Basically, an ounce of prevention it worth a pound or more of cure.
So strong focus on the goal/plants, keep them healthy.
Then algae never gets going or has a chance to germinate and bloom.

In low CO2/low nutrient systems, algae are still not limited, it's the light that limits them more than any thing, but this is a not a on/off switch, it's gradual and integrates many things we do as hobbyists, and often over look.

Just stick with plants and focusing on their needs, all algae issues are far less an issue this way.


Regards,
Tom Barr