I don't know about anybody else, but to me the greatest aquarium problem before the internet was "why is my tank green" and perhaps by no great coincidence 50% of the questions asked in the fit years of the aquarium fora on the Internet were of the same question. Now it's not discussed as much so we have answers we didn't know then, answers that came form a lot of poeple doing a lot of work and talking about it. Thomas Barr in the United States and Karel Rataj in Europe both wrote up the same approach, Rataj perhaps quantified it a little more.

On Jan 7, 2019 Jørn Ullits wrote:

Any way ... any use of hydrogen peroxide or other oxidation methods to kill the algae, is symptom treatment and is not a solution to get rid of algae at all... The cause to this BBA and algae in general, is different forms for sugars and sugar alcohols sieving/leaking from the plant the cause to these leaks, is access to missing nutrients which will cause deficiencies to the plants and make cell damages eg. to the leaves the reason is that the plants experience such an issue will move on the so called mobile nutrients and in the principle it gives up this leave .

Different algae types, different needs, because it seems that different lacks of nutrients that cause the leak also will leak different forms for sugars... the chemical formula for the leaking sugars will be different from each other if the lack of nutrient is different. So e.g. if the lack is phosphor/Phosphate, the most of you know that it will give spots on the leaves also called GSA Green Spot Algae... a pattern like Kalium/Potassium deficiency is often related to the edge of the leaves where the color changes to yellow/beige coloring--- it is often also here the BBA occurs so it is nearby to think there is a connection but as always there is an interaction between the different nutrients which have to be taken into account for the so called Mulders diagram or network.

There is no reason being afraid for the algae to spread, they don't unless as written there is a deficiency, BBA and several other algae is not as good as plants to make sugars, so it is a gift for them when plants is leaking these form for sugars and the algae, will place themselves directly on the leaves where the sugars sieve out of the plant and drill their 4 tabbed tongues into the leave, where they are stuck forever. So... if no other places/plants are leaking sugars etc. the algae will not spread.

So I'm with Tom Barr in this about taking care of the plants and specially about their needs, if this is fulfilled there will be no massive algae on them--- there will always be some form for micro-algae, which is perfect food for e.g. Otocinclus...

There is 5 parameters, you have to get balanced. The 2 first is the one which have to make demands and the 3 last has to fulfill their demands these is... 1. Light (intensity)
2. Temperature
3. CO2
4. Fertilizer/Nutrients
5. Circulation


Light and temperature if raised, will also raise the demands from the plants.. therefore the 3 last fulfilling parameters will have to be raised too.

- CO2 is the most important nutrient, so to say, because a plant anywhere on the planet is build of ca. 43% Carbon which is taken up in this way. - Fertilizers is needed for the plant to meet their metabolism demands or they will get sick and will get a behaviour as described with moving of some of the nutrients resulting in cell damages so this is an exercise the plant makes in a way to survive. - Circulation/flow has to be good, and will send the needed fertilizer and CO2 to the plants, .. it is very needed because the plants have never learned to move around by themselves, so these stuff has to come to the plants....

"any use of hydrogen peroxide or other oxidation methods to kill the algae, is symptom treatment and is not a solution to get rid of algae at all..."

Yup.

Paul Krumbholz used to advocate this method which worked for him. But he put plants in sealed containers. If you grow plants in a sterile environment, sure, sterilize everything, seal it up and you can't grow algae there.

In the rural works the spores are in the ir and it's going to grow, not growing algae is not an option. How you manage the growth is key.

Why is it we can spend five grand on a tank, put two grand of exorics slow goring pants in it and get algae while some noob can go out get a used tank from Craigslist nd put three batches od plants for the site in tnd for two years no algae at all. What is that?

The force, that's why. It surrounds all living plants and kills algae, the dark side of the force. The light controls this and the light side o fthe forsr is prwecul nd keeps the dark side at bay.

It's not really magic of course, but it's an easy way to conceptualise the complicated series of electrochemical reactions that occurs in living plants in culture. Long story short, you know that barely straw thing with ponds that kills algae? Peroxidases are why, they comes from rotting barley straw but are also generated by quickly growing plants and , not the same as but related to peroxide. Fast growing stem plants generate these in good light with ample food and enough of them are enough to hold algae at bay.

Barr told me this in 2005, Rataj pointed it out earlier and asserted 30% of the surface should be covered by fast growing stem plants.

When I hear "black/bba/staghorn" algae I look back on the 3 year fight I had with this menace and how it ended up everything Barr had been saying on the Aquatic Plants Digest ("APD") was true. Rataj had never put that into a book (dammit! why?) but did mention it on his website in the 1990s.

So now when I hear it I know: not enough plant food, not enough water changes and not enough fast growing stem plants. One of these along won't do it, two often won't, you need all three to have the kind of stable environment that is the only way you can grow the stuff.

Here's what I was told by Tom in 2005 to fix this and I never say it again:

1) Mechanically remove all you can.
2) Change all the water.
3) feed NO3 to 30 ppm
To which I added
4) Double dose with excel.


It's imperative you do this when the lights come on or the sun comes up. You're setting the state for a reason that requires light.

By that night the black algae should be pink and look very ill.

Do it again.

By the next night it should look white and dead. Siphon it all out and do it again.

You should not see it again.

Algae needs a stable environment to grow. Large water changes really hurt it badly. 50% water changes merely annoy it. 30% ones are more like a spa to it than anything else. Go big or go home, here.

For the record I wrote articles in TFH that advocated H202 and Bleach. I was young and foolish and this was a mistake. It's a waste of time to work against nature, and much easier to work with it.

Best plants I found for this: common Ludwigia, Pink Rotala, Hygrophila 'Ceylon'. (the orange/brown one)