• You are viewing the forum as a Guest, please login (you can use your Facebook, Twitter, Google or Microsoft account to login) or register using this link: Log in or Sign Up

What exactly causes BBA?

Jose said:
How do you know this plants arent phosphate limitted? even if you add some phosphates its still possible. Dont you think?
Click to expand...
I'm quite sure they are phoshate limited. And not only by phosphate. It's possible that they are limited by more then one nutrient. But why should I care ... if all the plants are in excellent condition with no visible algae? That's maybe the difference between us: You think that whenever plants are limited, they suffer and algae get upper hand. I think that whenever plants are limited, they just slow down (adjust) their growth to the amount of nutrients available to them. I don't believe that at lower nutrient level the plants must suffer and begin to leach something into the water which attracts algae etc.
I believe the nutrient uptake and growth follow this chart (in principle):
en_rostliny_ziviny_graf.jpg

So you can add 90 ppm NO3 + 9 ppm PO4 to reach the full growth potencial of your plants ... OR you can add less, and enjoy your plants growing at say 50%, or 70% or 90%. Why should I want for my plants to grow at 100%? What do I gain by it (except frequent trimming and much more work required on my side)?
According to some studies, some plants require 9 ppm PO4 to experience non-limited growth. So even under EI these plants will be PO4 limited. So what's the point?
 
PS: If there is any admin watching, it may be better if he/she can make a different thread from our "CO2 conversation" as I'm sure we are a way off-topic already.
 
Nope Im not saying limitting phosphates is a bad thing. I also consider it myself. Im just saying that for the experiment we were talking about you cant really limit anything otherwise you wont see the effect of co2.
 
Hi all,
ardjuna said:
You think that whenever plants are limited, they suffer and algae get upper hand. I think that whenever plants are limited, they just slow down (adjust) their growth to the amount of nutrients available to them. I don't believe that at lower nutrient level the plants must suffer and begin to leach something into the water which attracts algae e
Click to expand...
I think this is right as well.

All my tanks are nutrient limited, some of them have a lot of light, they all have a 12 hour photoperiod and I have very little algae.

There are certain provisos, I have "low tech" plants, all my tanks are jungles, I change some water every day, the fish mainly get live food and they've all been set up for while.

My aim is to keep the plants growing slowly. As long as they are in some growth I don't feed them, or do any tank maintenance other than the removal of dead leaves. I monitor the growth of a floating plant (not CO2 limited), and when the new leaves are small and yellow I feed. I started with Duckweed (Lemna minor) as my floater (hence the <"Duckweed Index">), but eventually I found the perfect "duckweed" was Amazon Frogbit (Limnobium laevigatum). It is perfect because it will grow over a large range of water parameters, and shows a quick greening and growth response to nutrients.

I don't monitor any parameters, other than an occasional dip with the conductivity meter, if the tank water falls outside of the 50 - 150 microS range I adjust it with our (hard) tap water or RO water back into the required range. There was nothing scientific about the choice of the conductivity range, it was just the range of values that our rain-water has (lower in the winter, higher in the summer).

cheers Darrel
 
In the upcoming experiment I don't focus on CO2. The CO2 will remain the same throughout the whole experiment. What will be different is the minerals content (mainly NPK+Fe). I would like to find out three things:
1) what is the concentration of nutrients needed for plants to hardly survive (we would say "stagnate")
2) what is the concentration of nutrients needed for plants to grow at the highest possible growth rates (100%)
3) what is the concentration of nutrients needed for plants to grow at 50% of these highest possible growth rates

So in the experiment I will add two plants (from the same kind) into each tank, and watch how long it will take for them to double their biomass (or to grow up to the water surface level). I estimate it can take a month for the plants in the first tank (the one with the lowest concentration of nutrients) to double their biomass ... and maybe they even stay the same for the whole month (may stagnate => the die off = new growth). Then I'll put this data into the chart similiar to the one I showed you in the post #101. It's basic scientific test where just one variable at a time may change (and that be the nutrient concentration). Light, CO2, temperature, flow, water parameters etc. will remain the same during the experiment. After I finish this experiment, I may do another one where CO2 will be the variable. But that would be a different experiment.
 
Hi Ardjuna,
But its not enough for CO2 to be constant. It has to be non limitting, otherwise your conclusions arent going to be based on nutrients only. Youll have to say in your conclusions: This are the nutrient levels........needed for (whatever your experiment)......but only for a certain co2 ppm. So if CO2 is limitting you wont get to the right answer.
 
Andy D said:
Sorry if I have missed this somewhere else (and I have not been on your site yet) but what do you believe causes algae? ... in general.
Click to expand...
If your question means "What causes ever present algae in our tanks to get out of control?" Then I have to say "I don't know what's the trigger mechanism(s)". But I know that it's quite easy and straightforward to grow algae in laboratories. You just put some algae in vegetative state into the petri dish, add the specified nutrient solution (anorganic nutrients, organic ones, vitamines etc.), and put it under light. After couple of weeks ... violá ... you have your algae! So growing algae is as easy as growing plants. Why do your plants grow like mad? What "causes" them to grow well? It's no magic. It's enough light + enough nutrients + time + friendly environment (incl. good water parameters). But our planted tanks are not always so friendly to algae, and the algae usually don't have enough time there to do their "growing". We have lot of algae-eaters there, frequent water changes, efficient filtration, the algae are often deprived of light by big number of plants, quite short photoperiod etc. So many factors are working against algae in our tanks. If you give them light + nutrients + time + safety environment, then you can expect them to prosper. That's how I see it ... in general.
 
In my tank its usually a build up of organics that cause BBA, so cleaning the filter plus a good clean up in the tank like syphon soil, clean all dead plant matter seems to stop more growth.


Also I found a quote by Yo-Han which I thought was very interesting....

some experiments I did....

I used my Vietnamese biotope as a test subject. This aquariumhas an overkill filter (Fluval U4) on an 10-12 gallon. I barely feed this tank and I do weekly 50% water changes. Almost no plants, and fertilizer whenever I feel like it. This means, plants are doing great sometimes, other times not so good. The tank is mainly filled with rocks and quite some flow (20x the tank volume). I can keep all these things constant and am able to induce BBA and stop it from growing by one simple change... oxygen!

When I aerate the tank 24/7, no BBA at all. When I stop aerating, BBA pops up. Aerate again and it stops growing (it doesn't die). Not sure whether it is the direct effect of the high oxygen, or the fact that all organics are broken down easier. But with the mass overcapacity of the filter and low organics due to little dying plants and littlefish food, I almost expect the direct effect.

In my other tank I use CO2, but by keeping the tank clean, I reduced the oxygen demand of the organics, and thus raised the amount of oxygen as well. When people use more CO2 and conquer BBA, they raise the amount of O2 as well, by making their plants produce more.
Click to expand...
 
I dont think his conclusion is totally right though. I think it might have something to do with the algae detecting a certain substance/es. This substance might come from organics or maybe from suffering plants as well. So by upping O2 maybe what Johan was doing was making his filter work more efficiently to reduce this substance. In other words: o2 isnt the cause/solution directly. I think this way because in other tanks adding more O2 doesnt fix the BBA.
 
ardjuna said:
You just put some algae in vegetative state into the petri dish
Click to expand...
Hi Ardjuna,
Is it as easy to grow it from spores in that situation? Or is it possible they need a different mechanism to grow activate ?
I ask because;
some folks set up a new tank, 'scape, etc and get algae problems (presumably from spores) and other folks don't,
some folks have algae and get rid of it easily, others don't.
So there are possibly 2 separate problems; a dormancy trigger mechanism and an active continuance.
I hope that makes sense..

Good luck with the experiments, I can see with all the permutations it will be a lot of work.
cheers phil
edit - changed 'grow' to 'activate'
 
sciencefiction said:
I read it and it still doesn't mean much to me. Even my low tech tanks do better with more light contrary to what I read around and plants suffer if the light is reduced so it's not just co2 that plays a role in those "best looking tanks". So the way I read it is that if you put 6-7 watts per gallon(of what type of light) you need to pump obscene amounts of CO2(how much exactly and how did you measure the dissolved co2 that is indeed available to plants?) and you get the best looking tanks that's you've done(about which I won't argue, they probably are)


From all those "arguments" to me it seems that the biggest problem is that it's hard to dissolve and distribute the co2 in a way so that most if not all of that pumped co2 doesn't just pass by and out the door before the plants have got a glimpse at it. Most people just presume on given tables and ph profiles what the co2 level is but in fairness no one knows for sure or do we? And then again we argue that higher than this or lower than that is best. Maybe the 30ppm you pump in actually gives you a stable 10ppm? 🙂

Is there a way to measure for sure the amount of dissolved co2 in water that is available to plants in a particular aquarium near a particular plant?
Click to expand...

I never have used a drop checker or ph meter. In the tanks I mention, they were not great but were the best I did myself.
I think titration is the only method economically viable, but probably not relevant to our needs.
You maybe right about actual ppm values it is very difficult to economically evaluate, but plant growth and health is best indicator. Light, High co2 and low light has always failed for me, usually resulting in cyanobacteria, diatomic algae and rotting stems, this does not mean it fail for everyone else though. Replicating conditions which gave success in the past seems to be very difficult at times. I have no answers I am sorry to say, just having fun trying different things.
Sometimes walking away and not looking at the tank for 3-4 days improves them a lot! :lol:
Fishes and shrimp make people to walk on a knife edge with co2, I do not personally keep fishes in experimental tanks or high co2 tanks, but many do, with good success.
 
Jose said:
I dont think his conclusion is totally right though. I think it might have something to do with the algae detecting a certain substance/es. This substance might come from organics or maybe from suffering plants as well. So by upping O2 maybe what Johan was doing was making his filter work more efficiently to reduce this substance. In other words: o2 isnt the cause/solution directly. I think this way because in other tanks adding more O2 doesnt fix the BBA.
Click to expand...

What substance do you have in mind that the filter bacteria in conjuction with oxygen actually reduces? All I can think of is ammonia. By increasing oxygen, the nitrifying bacteria will oxidise the ammonia produced faster, thus not leaving it available to algae which loves ammonia. This should be the job of the plants too, but if they are suffering at that moment and actually produce more organics than ammonia they can consume/oxygen they can produce, then good filtration and extra high oxygen via other means is the redundancy mechanism.
When you increase oxygen, the organics also break up faster by other type of bacteria responsible for that. The organics probably break up into many different forms like ammonia, even nitrite, CO2, other minerals and substances, etc.. and from there they are picked up again by other things like nitrifying bacteria, plants etc.. The algae on another hand, maybe capable of extracting its food directly from organics before they are broken down by bacteria, unlike plants that need them in a different form, so when organics are reduced by high oxygenation, algae has less food to thrive on. It's the rule I follow in my low tech tanks and it works against algae. From 5 tanks, I've only battled algae in one in years, and as I mentioned before, it's an overstocked tank so I can't help it unless some fish die off(hopefully not) But it hasn't had algae in about 6 months now, since which time I added an airstone, never even thought about it till today to be honest. It could be a coincidence. My tanks are low tech, high surface movement, overfiltered, large weekly water changes, moderate light the least if not even high, all unlike the typical low tech tank. And that doesn't produce algae at all if stocked accordingly.

And I've actually experienced what Yo-han says above. I had a brief encounter with BBA in one tank years ago, on the dwarf grass on the bottom, soon after setup. I started it with one sponge filter which tended to clog and barely move water in and out. I added a 2nd filter and an air stone, cut off the bba affected grass and I never saw bba again in this tank.
What he says makes sense to me.
 
Last edited:
Another Phil said:
there are possibly 2 separate problems: a dormancy trigger mechanism and an active continuance.
Click to expand...
That's the "spores vs. vegetative cells" controversy.

T.Barr says that in our tanks there is a great number of algae spores which are just waiting for some trigger mechanism(s) to "activate" [germinate] them, and then they start to grow like mad. If you want to know what may be the trigger to germinate algae spores, look at this article.

I myself tried to analyse more than hundred water samples from different aquriums under the microscope, and to be honest I was not lucky enough to find any one single algae spore. I'm not saying we don't have algae spores in our tanks, but in my opinion 99.9% of algae present in our tanks are in the form of vegetative cells. For algae to go into the dormant state (spore) it needs to experience some extremely unfriendly conditions ... otherwise it's just keeps to grow and multiply.

So the whole fight for finding out what "triggers" algae is useless according to me. As if most algae are in vegetative form, then they don't need to be "triggered" to grow. They just need a few things for them to multiply enough. So why they don't bloom in our tanks if they are ready to do so? I think that the main reason are the "inhibiting factors" which hinders them (low pH, algae-eaters, frequent water changes, low organics, efficient filtration, relatively low light intensity, big amount of plants, high levels of oxygen, high redox, good maintenance, low fish load etc.). This all may contribute to keeping algae at check. If you watch carefully your algae-eaters, you'll see that on all plants and decorations (= just everywhere) there are actually algae growing, and the shrimps and other algae-eaters are constantly eating them. If there were no algae growing, our algae-eaters would probably die. So don't think that in your (or anyone else's) tank there are not any algae. The algae are always present and growing. But if the conditions are not opportune then the growth is very slow. The same is true with our plants. Some aquarists have problems growing aquatic plants. This means that they don't understand what the plants really need and how to provide it to them. Once they provide their plants with everything they need, they'll just grow fine (and sometimes even they'll grow like mad). The "only" problem which makes it hard for us to grow our plants (and sometimes easy for algae to grow like mad) is that aquarium is quite complicated ecosystem with a lot of variables and different factors which sometimes we are just not able to control very well (mainly because we just don't know how they relate with each other ... we are not enough educated or use strange equipment, water, substrates etc.). I would recommend each aquarist who want to learn grow plants, to first start with growing terrestrial plants. This is very good for aquiring the basics (what plants need, which soil, how many nutrients in water, how much light etc.). The terrestrial plants (houseplants) are quite easy to grow as they require just very few things (good soil, rather mild watering, and good light). With aquatic plants it's harder as you have more factors coming into play underwater (mainly different water parameters, bad soils we sometimes use, bad filtration, unbalanced nutrition, algae etc.). As we often don't see the correlation between nutrients, light, algae, water parameters, soil ... we are then often experiencing so many problems.
 
Edvet said:
Which volume? did you use a centrifuge?
Click to expand...
I did not use any laboratory methods of analysis, so I did not used a centrifuge as I don't have access to any. I just sampled algae from different places in different tanks, and look at them under microscope. But I discussed this matter also with several algologists who confirmed that it's very rare to find out any spores under normal circumstances (like the ones in our tanks).
 
You must log in or register to reply here.
Back
Top