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Phosphate is the king of the planted tank

:thumbup:, focus on healthy plants and the algae isn't an issue

I agree totally with that sentiment, if you have a large mass of healthy growing plants, algae seems to be naturally minimised. However I’d love to know the true technical reason why that is the case. I’ve searched extensively and I can’t find a water tight reason why.

I often read the phrase that the ‘plants outcompete the algae’, but that sounds like nonsense in an environment where we purposely ensure excesses of all nutrients and freely available CO2, unless plants are releasing some sort of hormone or enzyme as they grow which inhibits algae.

My own personal thought is that large quantities of healthily growing plant mass ensure consistent DO saturation in the water column, and I assume in general terms DO saturated water is a an unfavourable environment for most types of algae.

That would suggest though that we could artificially inject O2 to achieve the same thing. I know Tom Barr tried this at one point, and didn’t find it conclusive, which suggests there may be other things at play.
 
Hi all,
There are more algae species than higher plants, and more factors than algae that can cause outbreak. So attempt to identify one factor, such as phosphate, as a cause of algae is futile.
My guess is that you are right, I think "futile" would be stronger than I'm willing to go, but certainly "difficult to quantify".
and I assume in general terms DO saturated water is a an unfavourable environment for most types of algae.
Depends on the algae, there are algae that are adapted to <"clean, highly oxygenated">water.

In eutrophic conditions you can end up with very high oxygen levels, I've seen <"pearling algae in sewage works">, at <"Canford Park"> etc.
I had an interesting one today. I won't tell you the location, or context, but it was a pond and the water sample had a dissolved oxygen level of 180% (~20oC, 18mg/L DO) and a pH value of pH 10.5.
.....that the ‘plants outcompete the algae’, but that sounds like nonsense in an environment where we purposely ensure excesses of all nutrients and freely available CO2, unless plants are releasing some sort of hormone or enzyme as they grow which inhibits algae.....
We don't know why a large plant mass works to reduce algae, Diana Walstad thought it <"might be allelopathy">, but I'm not sure anybody really knows.

cheers Darrel
 
Hi @Wookii
I often read the phrase that the ‘plants outcompete the algae’, but that sounds like nonsense in an environment where we purposely ensure excesses of all nutrients and freely available CO2, unless plants are releasing some sort of hormone or enzyme as they grow which inhibits algae.

In Diana Walstad's book*, there is a table of allelopathic compounds (found in aquatic plants) and the organisms on which they act. Apparently something called a-asarone and linoleic acid both act on algae and cyanobacteria. She also references the scientific papers from which this information has been taken. I am beginning to realize that the information that's often missing in our hobby really is out there!

* You know the one - Ecology of the Planted Aquarium

JPC
 
In eutrophic conditions you can end up with very high oxygen levels, I've seen <"pearling algae in sewage works">, at <"Canford Park"> etc. We don't know why a large plant mass works to reduce algae, Diana Walstad thought it <"might be allelopathy">, but I'm not sure anybody really knows.

cheers Darrel

In eutrophic lake, not only O2 is streaming but CO2 is stripped to near zero at high noon leading to large pH swing as mentioned in Walstad book. But natural waters are not algae free and rarely have as high plant mass as in planted tanks. Only urban creeks and storm water ponds have choking high plant mass that is considered weed and need to be cleared with herbicide or dredging to restore flow.
 
Hi all,
........... must have a hypothesis
Not really. Allelopathy might be <"one of the reasons">, but I'm pretty sure it isn't the only one.

How the microbial assemblage in the substrate changes would be really interesting, both in terms of the actual microbes and their relationship with the plants, and I think a lot of scientific research is looking at this.

The number of nitrifying organisms has <"increased exponentially"> since we could look <"for genes"> that coded for ammonia oxidation etc. and my guess would be that is only the beginning and that all sorts of interesting microbial relationships will be found once people have the tools to look for them.
But natural waters are not algae free and rarely have as high plant mass as in planted tanks. Only urban creeks and storm water ponds have choking high plant mass that is considered weed and need to be cleared with herbicide or dredging to restore flow.
You would find a some-what different view in some of mainland Europe where they have attempted to <"treat the cause">, rather than just <"the symptom">.

In the UK and USA I think we often looked for a quick fix for short term economic reasons, rather than a <"more expensive long term solution">.

You can get a combination of clean water and heavy macrophyte growth, we still have a number of chalk streams in England that are <"relatively undamaged">.

Ranunc_ninehatches_Jess.jpg


cheers Darrel
 
I'm just wondering why this topic turned to complaining about one of the most important "eyelets" in an aquatic "chain" of food? Be it a food for plants by decomposition of algae (great source of primarily N, P and and partially Fe+P) and be it a food for the fish, shrimps etc when their diet is extremely dependent on existence of algae at all. I think tendency to completely removing algae from our tanks can lead to serious problems in the tank stability, especially when we keep fish, shrimps, bugs etc in it.

Algae is a MUST in environmentally stable tank and I can't imagine wellbeing of my shrimps, snails, fish and tonnes of various bugs without them.
 
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I think tendency to completely removing algae from our tanks can lead to serious problems in the tank stability, especially when we keep fish, shrimps, bugs etc in it.

Algae is a MUST in environmentally stable tank and I can't imagine wellbeing of my shrimps, snails, fish and tonnes of various bugs without them.

This is why I posted asking why I had none on my rotala. It was alarming. As I expected an algae bloom after all my re-scape and aggressive trim. But there was none.

However, I was pleasantly surprised when I woke up to see that little spot of GSA. Still nothing on the rotala.

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On a side note:

What is going on here (see below); the rotala pushed out some leaves (while it transitioned?) and decided later to fill them out?

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These thin tissue-paper like leaves are - I am assuming healthy - photosynthesizing 🤔 ... so healthy, thin tissue that it will pack on the rest later?
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Josh
 

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Hi all,

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

As you know, on Saturday, I reduced my light which I think was a rash move - we live we learn - I am becoming slowly becoming more patient ... be patient with me :D. I genuinely thought that it was a safe move - and in many ways I wonder if the reduction in light is what allowed my plants to fill in, in my post above - maybe once we know what they are doing, then we will know?

Of course, my CO2 was dialed in for more than 25% more light. I noticed late (by one day I think), but one of my fishies began to gasp (which I have not seen for a while) - in fact, with the increase in light, everyone looked more lively. So, instead of freaking out as I have done in the past, I simply turned off the gas and turned my lights off 1 hour later.

This particular fish (a lampeye that snuck into my bag at the fish store the other day ... thinking I'll increase the school for him) gasped for at least 45 minutes (even after the CO2 was off), then resumed life. As a result, I increased my light (warm white and cold white by 10% this morning ... I was tempted to go for the big 100, but I withheld). Today, he was ok but gasped for only 5 minutes after gas off.

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.

The GSA in the post above, may be related to the change in the drastic change in my light, throwing the system off the enigmatic balance, or it was simply a coincidence ... which is very likely :D.

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

Another very neat observation I had (and these are just solidifying things I have read):

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2 substrate shots above from the hacked (and mature) side of my s.repens carpet (left) and the freshly planted, immature, side (right).

The gas in the substrate was remarkable to see - is it CO2 that is produced by bacteria in the rhizosphere?

If it is, then the plant should be able to move these gases (as I mentioned earlier towards my assertion that this would be why crypts melt?) to help with growth?

Josh
 
This is why I posted asking why I had none on my rotala. It was alarming. As I expected an algae bloom after all my re-scape and aggressive trim. But there was none.
I've posted this photo in another thread related to some deficiency:
https://www.ukaps.org/forum/threads/holes-in-leaves.61746/#post-608378

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Would you believe that there is no even a single sign of algae in that tank? (I can upload more imgs tomorrow if needed). Ok, there are some algae but visible only when I use quite big magnifying glass (and I use it quite often), but algae are absolutely unnoticeable generally - and it lasts like that for 3 months or so for now.

And I think that when we keep our plants in the "starving" zone algae have not even a single chance to appear because they are outcompeted by more hungry competitors.

And because of that I have another tank full of GTA and I move some part of them to my main tank occasionally :)
 
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Would you believe that there is no even a single sign of algae in that tank?
I believe it. It would be fascinating to see some microscopic pictures of the leaves also. Have you achieved the holy grail of TOTALLY algae free system?
 
Tell you what boys, focusing on plant health is fine but it doesn't work EVERYTIME. Sometimes algae can win regardless. Shows how little we know.
 
It would be fascinating to see some microscopic pictures of the leaves also.
Hey @rebel This is actually great idea. I have this cheap CN "microscope"

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and this is what it shows:
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Wed Jul 29 13-41-29.jpg


The surface of damaged and undamaged leafs of Bacopa caroliniana looks identical, but I don't know if it's an algae or actual leaf tissue. Maybe @dw1305 could have look? Darrel, what do you think?
 
Hi @Wookii


In Diana Walstad's book*, there is a table of allelopathic compounds (found in aquatic plants) and the organisms on which they act. Apparently something called a-asarone and linoleic acid both act on algae and cyanobacteria. She also references the scientific papers from which this information has been taken. I am beginning to realize that the information that's often missing in our hobby really is out there!

* You know the one - Ecology of the Planted Aquarium

JPC
Walstad is a believer of alleloppathy and has devoted a whole chapter on the subject in her book. Tom Barr is a nonbeliever and has argued and conducted experiments to prove its absence. Dennis Wong is silent on the subject, either he is skeptical, a nonbeliever, or simply doesn't know. All agree that healthy plants have no algae, but have no consensus on why.

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.

Walstad cited ecological studies extensively in her book, sounds scientific, but natural environment is different from glass box environment. In fact, I don't think "ecology" is relevant to an artificial system.

I am in the opinion that alleloppathy may exist in certain plants, but not widely. I read that Hornwort can secret chemicals that suppress algae, and that Nymphaea roots can stunt neighboring plants. I have no experience with Hornwort and my Nymphaea is grown in hydroponic pot, so I don't know how true it is. 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.

Even healthy plants have some algae, just not the visible ones. The goal is to grow healthy plants without excessive, obnoxious and ugly algae. Small amount of GSA, GPA, green or brown algae is fine, and will be taken care of by algae eaters and provide food for fish. BBA is ugly and even tiny amount is objectionable. BGA is obnoxious, and any presence above the substrate must be eliminated.
 
Hi @tiger15
The goal is to grow healthy plants without excessive, obnoxious and ugly algae. Small amount of GSA, GPA, green or brown algae is fine, and will be taken care of by algae eaters and provide food for fish. BBA is ugly and even tiny amount is objectionable. BGA is obnoxious, and any presence above the substrate must be eliminated.

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
 
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