Phosphate is the king of the planted tank

[jaypeecee]

Hi @tiger15

If indeed plants secret alleloppathic chemicals to suppress algae in the surrounding, the quantity produced must be so huge to overcome dilution from water current.

...unless this phenomenon has been observed in natural waters where there is minimal/no flow? Just a thought.

JPC

 

[Zeus.]

But, I'm not sure if cyano/BGA in the substrate is acceptable

I have it in my substrate, or did, it comes and goes in a few spots but has never been an issue. Even stopped checking it in last 12 months.

 

[sparkyweasel]

Walstad deduced the presence of alleloppathy by her personal failure to grow certain plants together but fine if grown alone. Barr argued that he has no problem growing many plants together given the right CO2 and conditions.

The difference may be related to Walstad's preference for minimal (at one time zero) water changes.

 

[rebel]

The difference may be related to Walstad's preference for minimal (at one time zero) water changes.

Or any of the other variables either measured or non-measured.

 

[tiger15]

I have it in my substrate, or did, it comes and goes in a few spots but has never been an issue. Even stopped checking it in last 12 months.

BGA is nitrogen fixing. Isn’t it beneficial to have some in the substrate, sort like growing legumes to enrich garden soil. BGA is the first phosynthetic organism and ancestor of chlorophyll in higher plants.

 

[JoshP12]

Hi @tiger15


Yes, I couldn't agree with you more - we're on the same wavelength. But, I'm not sure if cyano/BGA in the substrate is acceptable either. Having said this, I recognize that other people have different thoughts on this topic.

JPC

BGA is nitrogen fixing. Isn’t it beneficial to have some in the substrate, sort like growing legumes to enrich garden soil.

I have it in my substrate, or did, it comes and goes in a few spots but has never been an issue.

I don’t have much to contribute to the recent conversation, but I’ve been loving it!

Perhaps there is a difference between a large mat that takes overs and a non-zero amount in the substrate?

Cyano is nitrogen fixing - like nitrosomonas?

Josh

 

[dw1305]

Hi all,

In fact, I don't think "ecology" is relevant to an artificial system.

I'm not going there, you definitely can have an approach to aquarium keeping that ignores ecology, but I think only heart-ache and tragedy lies down that particular route. Even with micro-management of water parameters soon or later you will have problems. An <"ecological approach"> builds in complexity and resilience and does away with a lot of <"single points of failure">.

BGA is nitrogen fixing.

Some are, some aren't Oscillatoria is <"non-diazotrophic">.

Cyano is nitrogen fixing - like nitrosomonas?

No that nitrogen is already "fixed". Some bacteria can <"anaerobically split the triple bond"> between nitrogen atoms (in gaseous nitrogen (N2)) and then incorporate the nitrogen atoms into other compounds. The <"mycorrhizal symbionts"> of legumes (Rhizobium) are the most famous, but there are others.

isn’t it beneficial to have some in the substrate, sort like growing legumes to enrich garden soil.

May well be, there is definitely transfer of fixed nitrogen from the symbiotic <"Anabaena in Azolla "> to Rice in paddy fields.

unless this phenomenon has been observed in natural waters where there is minimal/no flow?

Hornwort (Ceratophyllum demersum) would occur in still water. I was just looking at an interesting paper <"Influence of Daphnia magna and Ceratophyllum demersum on the control of algae under different phosphorus concentrations">

.....the influence of Daphnia magna and Ceratophyllum demersum on the control of algae under different phosphorus concentrations, Cyclotella sp., Microcystis aeruginosa, and Chlorella vulgaris were selected............. phosphorus concentration ranged from 0.05 to 2 mg L−1, C. demersum imparted a significant inhibition of the three species of algae, particularly M. aeruginosa. The total growth rates of the three species of algae were reduced with higher phosphorus concentrations; however, the effect was lower than that of D. magna, with C. vulgaris as the dominant species. When the phosphorus concentration ranged from 0.05 to 2 mg L−1, D. magna combined with C. demersum inhibited the growth of the three species of algae to a considerable degree, which was an improvement over that of other experimental groups using only D. magna or C. demersum by themselves. The total growth rates of algae were reduced with higher phosphorus concentrations. When the phosphorus concentration ranged from 0.05 to 0.1 mg L−1, the removal rates of phosphorus exceeded 90%, and the phosphorus concentration became the limiting factor in the culture system.

Even if strict allelopathy (I'm also agnostic as to how important it might be) doesn't exist in terms of plants producing antimicrobial chemicals, it certainly <"exists in the rhizosphere"> where plants are actively altering the microbial assemblage to gain nutrients and using these microbial cohorts as soldiers in proxy wars with other plants.

It isn't surprising that <"antibiotics were isolated from soil bacteria">, cyanobacteria, actinomycetes, "fungi" etc have been waging biological war on each other for billions of years. That is partially why I'm agnostic about strict allelopathy.

cheers Darrel

 

[JoshP12]

As this thread keeps moving forward, I think I will update on a few things that I noticed regarding O2/CO2/Light/Plant growth.

...

Clearly, the increased PAR gave rise to higher CO2 assimilation and increased oxygen production, influencing my O2:CO2 ratio, in turn making it healthier for my fishies. Tomorrow, I will increase again and see what happens.

**of course, I could have turned down the CO2 ... instead of pursuing that avenue, I decided to pursue light.

Josh

For anyone following the CO2 journey! After my 10% increase, no sign of distress on fish ... it only looks healthier (went for a 5'er today).

Now, for the cool thing! In the graph below, you can see the pH being monitored (every minute a reading is taken and graphed). You can clearly see when CO2 turns on and when it turns off. What is interesting is the most recent drop that you see (the "third" one or yesterdays) is more "stable" and if you were to draw a smooth curve through it, you would see the lowest point is higher:
10% increase light,
fish look healthier,
more CO2 is being absorbed,
less pH drop 😳




Although it would have been nice to see what today brings on a 5% increase, I had to get the Dissolved Oxygen probe running again - it would be cool to see if the supersaturation actually occurs.

They shouldn't bother each other, but it threw my pH reading off (down to 1.1 😛).

Josh

 

[Wookii]

For anyone following the CO2 journey! After my 10% increase, no sign of distress on fish ... it only looks healthier (went for a 5'er today).

Now, for the cool thing! In the graph below, you can see the pH being monitored (every minute a reading is taken and graphed). You can clearly see when CO2 turns on and when it turns off. What is interesting is the most recent drop that you see (the "third" one or yesterdays) is more "stable" and if you were to draw a smooth curve through it, you would see the lowest point is higher:
10% increase light,
fish look healthier,
more CO2 is being absorbed,
less pH drop 😳


View attachment 152620

Although it would have been nice to see what today brings on a 5% increase, I had to get the Dissolved Oxygen probe running again - it would be cool to see if the supersaturation actually occurs.

They shouldn't bother each other, but it threw my pH reading off (down to 1.1 😛).

Josh

What DO meter do you have? It would be interesting to see a similar graph for DO during the photo period and with the changes in CO2 - I've been wanting to get a DO meter myself for some time, but they are a little cost prohibitive.

 

[JoshP12]

What DO meter do you have? It would be interesting to see a similar graph for DO during the photo period and with the changes in CO2 - I've been wanting to get a DO meter myself for some time, but they are a little cost prohibitive.

Well I tried to run both the DO probe and the pH probe at the same time, but they interfere ... they shouldn't though 😡 - it dropped my pH reading to 1.1 ...it may be detecting some voltage from the other probe.

The test system is a Vernier.

I have the DO probe running right now - running a similar thing.

I am actually curious myself on < the effect of CO2 on the photolysis rate >.

My lights turned on 35 minutes ago.
My plants on the left began to pearl 15 minutes ago, the ones on the right about a minute after.
The graph below shows that from lights on, my DO has gone up by ".2" (the 21 minutes is because I got the "graph test" going later than lights on .. but it was in the water).



Ignore the 4.9 ... it can't be right. I run my tank at 72 fahrenheit. I skipped the in depth calibration because we just had a massive thunderstorm and I don't know the pressure outside ... I'll just calibrate some point later when the weather seems calmer.

What is important is the system is warmed up and the reading was consistent for about 10 minutes. I hope the 4.9 is more like 8 😛.

EDIT: I am not sure if it is a coincidence but when the pearling started, it lines up with the minor blip into stability 😳 ... @dw1305 -Darrel ... coincidence or is it a valid observation?
Could it in fact suggest that that particular location (although O2 varies in the tank and it is not a good indicator of the ENTIRE tank) could be good "enough" that the water is saturated while, at the same time, the area around the leaves are saturated?

Josh

 

[dw1305]

Hi all,

I've been wanting to get a DO meter myself for some time, but they are a little cost prohibitive.

If they were cheaper they would definitely be on my list of <"easy to use equipment">, along with <"conductivity meter and glass thermometer">.

Ignore the 4.9 ... it can't be right.

No it won't be, are you at altitude?

Where the oxygen level stabilises depends on a <"number of factors">, but assuming you have reasonable flow it should be at, or just above, 100% saturation all over the tank. You'll need to get the %DO from the <"conversion chart"> if you've recorded in mg/L.

@Geoffrey Rea 's experiment with a dissolved oxygen meter and filter flow is also interesting.

cheers Darrel

 

[JoshP12]

Hi all, If they were cheaper they would definitely be on my list of <"easy to use equipment">, along with <"conductivity meter and glass thermometer">.

cheers Darrel

For what it is worth, I did not buy these.

I am borrowing them so that we can utilize them in my school with students. If I can find a practical use and draw some real conclusions, I can hopefully start a club and engage learning.

This semester pre-covid, we were going to go to a nearby lake.

Josh

 

[Wookii]

Well I tried to run both the DO probe and the pH probe at the same time, but they interfere ... they shouldn't though 😡 - it dropped my pH reading to 1.1 ...it may be detecting some voltage from the other probe.

The test system is a Vernier.

I have the DO probe running right now - running a similar thing.

I am actually curious myself on < the effect of CO2 on the photolysis rate >.

My lights turned on 35 minutes ago.
My plants on the left began to pearl 15 minutes ago, the ones on the right about a minute after.
The graph below shows that from lights on, my DO has gone up by ".2" (the 21 minutes is because I got the "graph test" going later than lights on .. but it was in the water).

View attachment 152621

Ignore the 4.9 ... it can't be right. I run my tank at 72 fahrenheit. I skipped the in depth calibration because we just had a massive thunderstorm and I don't know the pressure outside ... I'll just calibrate some point later when the weather seems calmer.

What is important is the system is warmed up and the reading was consistent for about 10 minutes. I hope the 4.9 is more like 8 😛.

EDIT: I am not sure if it is a coincidence but when the pearling started, it lines up with the minor blip into stability 😳 ... @dw1305 -Darrel ... coincidence or is it a valid observation?
Could it in fact suggest that that particular location (although O2 varies in the tank and it is not a good indicator of the ENTIRE tank) could be good "enough" that the water is saturated while, at the same time, the area around the leaves are saturated?

Josh

Thats interesting.

4.9mg/l could be fairly realistic - is your basic/non-in-depth calibration likely to be 60%+ inaccurate? I'd doubt if the plants would manage to saturate the entire water column within half an hour - @dw1305 might have an idea of how long this might take (though it would depend on plant mass and numerous other factors, so may be a 'how long is a piece of string?' type question). You'll be able to tell later anyway if the reading gets above 8ppm.

 

[JoshP12]

You'll be able to tell later anyway if the reading gets above 8ppm.

It's at 5.1 .

I have it on a 3 hour interval, so I will try to snip the data from today and post later 😀.

Josh

 

[JoshP12]

No it won't be, are you at altitude?

Not at all 😀.

 

[dw1305]

Hi all,

Not at all

is your basic/non-in-depth calibration likely to be 60%+ inaccurate?

Can you re calibrate the meter in 100% water vapour saturated air?

All the DO meters I've used have been pretty good, unless the membrane is damaged.

cheers Darrel

 

[JoshP12]

Hi all, Can you re calibrate the meter in 100% water vapour saturated air?

All the DO meters I've used have been pretty good, unless the membrane is damaged.

cheers Darrel

Not sure about the air (unless you have a trick); what I have is a gasket seal (with water in the bottom) and I have to input the number based on my pressure outside. I also have a 0 oxygen solution that I can use.

Side note - here is the data:
1st part of photoperiod
Second part of photoperiod
Third part of photoperiod to lights off.

It is at "4.1" now ... I think it is off by 4. I am running a long cycle now and will recalibrate either at the end or stop it in between to do so!

A supersaturation actually occurs 👍.

Second side note: Does anyone have that link where Tom Barr suggests that CO2 mist increases photosynthetic rate by 25% and he tested it with DO probe and saw an increase in DO levels? I just recall either skimming it and finding it or reading it from someone else. His work may answer my question about photolysis being influenced by something other than light.


Cheers,
Josh

 

[dw1305]

Hi all,

what I have is a gasket seal (with water in the bottom)

When you calibrate the probe it should be in the air above the water, not actually in the water. If you don't know what the atmospheric pressure is you can use 1000 mbar and it won't be far wrong. Wikipedia gives you the <"conversion factors">.

Side note - here is the data:

That is definitely not quite right.

If it is an old meter there may be a tear in the semi-permeable membrane? If it is a new meter there might still be a seal or cover somewhere that needs removing?

I actually use the fish tanks to make sure the <"membranes are OK">. When the lights are on I pop the probe in the tank, if it doesn't equilibrate to ~100% saturation pretty quickly then I know the membrane is damaged.

cheers Darrel

 

[zozo]

I don't think "ecology" is relevant to an artificial system.

If you look at Tapwater under a microscope you will find bacteria and algae spores... If you put tap water in a transparent bottle and neglect it for a while, you will find a biofilm developed to its inner wall. Put it in a light spot the algae will reproduce and grow.

All this simply is Ecology in a bottle... 😉

The definition of Ecology is

a branch of biology concerning interactions among organisms and their biophysical environment, which includes both biotic and abiotic components.

I guess David Wong is silent about some issues because he probably is the smartest of them. He likely realizes that the debate about the relevancy in ecology is too subjective. I think you are correct that he simply doesn't know...

The Eco part of the definition is a mother nature invention, we can't get around, only she decides it's relevancy. The Logic behind it is a human invention and in this, it's only what you see is what you get is relevant... It doesn't actually proof that much... For example not finding any only proofs you didn't find it...

 

[Wookii]

@Geoffrey Rea 's experiment with a dissolved oxygen meter and filter flow is also interesting.

cheers Darrel

Do you have a link to that thread Darrel? I vaguely remember reading it, but I've searched and can't see to find it now.