My Algae Playbook (After last years experimenting)

[jarrod0987]

I'm not understanding what you're doing here. Can you go into a bit more detail?

Basically, I wanted to find out why my soil was denitrfying and no one else's. I realized it might be the wood and not the soil so I separated them. I set up each one separate to see which one caused the effect. It was the wood.

I would love the nitty-gritty on this actually.

What would you like to know. Maybe phone call? lot to talk about

I'm still not buying it, but I'm not going to dismiss your observations so easily. I would offer the following thoughts.

Appreciate that very much. I have respect for this kind of criticism vs the usual kind I usually get.

1) Wood chips are acting to somehow sequester nitrates rather than a medium for nitrification.

I thought about this and I have not ruled it out. The effect does slow down after a year. Might be wood got full. Might be wood broke down. When I autopsy this tank I will know.

2) The wood is releasing 'something' that's interfering with your tests.

Also possible however...my plants showed signs of nitrogen deficiency until I started dosing it. This is not conclusive of course. Also...I can add nitrate at any level to that tank and then run a nitrate test. Either API or LaMotte and the result comes back about right after 1 hour of letting the water stir etc.

3) The wood is somehow essential for a secondary process that's fueling consumption of nitrogen products.

Not sure exactly what you mean but I also suspect the carbon compounds int he wood might be important. The whole reason why nitrate gets consumed is for respiration when no O2 is around. The reason for respiration is carbon consumption. The would is breaking down after all.

Lot of hand waving, I know.

But I also would throw out the following thought: If adding woodchips causes denitrification inside the woodchips (as you suggest), why wouldn't hunks of driftwood be nitrate sucking machines?

I am wondering if it is a surface area issue. Perhaps also a rate of water soaking in and out/surface issue. I have been told by others that there tanks with a lot of drift wood has lower nitrates then other tanks but I have never kept a tank like this.

Surely it's anoxic inside them. Also, if it were truly anoxic, wouldn't you have sulfurous reactions taking place instead. I've certainly had that happen accidentally before.

When I disturb the soil I definitely smell the sulfur. Also....there are many possible electron carrier reactions for bacterial respiration. I think at least 8. They go in order...O2, then NO3,...something something... Sulfur is in there somewhere. Walstad talks about them in her book. Has them all ranked etc. The formulas are all there.

You have my respect for the way you are conducting yourself while we are debating. I will be happy to share with you what ever you wish. I have time off this next few days. If you wish we can talk about many things.

 

[aqua_chem]

Basically, I wanted to find out why my soil was denitrfying and no one else's. I realized it might be the wood and not the soil so I separated them. I set up each one separate to see which one caused the effect. It was the wood.

Yea, but I wasn't following with what you were saying about tanins and bacterial activity.

What would you like to know. Maybe phone call? lot to talk about

That would be easier, but the simple advantage is that if you were to type it out, it would be preserved online and searchable if anyone decided to look for it. I can see someone seeing something similar and googling his question only to find this thread and being really frustrated by the lack of detail, see?

Appreciate that very much. I have respect for this kind of criticism vs the usual kind I usually get.

There are lots of people out there that are certain of their opinions with no reason to be. Best to lead by example and all that.

IN REGARD TO NITRATE ABSORPTION

I thought about this and I have not ruled it out. The effect does slow down after a year. Might be wood got full. Might be wood broke down. When I autopsy this tank I will know.

Will you? How could you tell?

IN REGARD TO TEST INTERFERENCE E

Also possible however...my plants showed signs of nitrogen deficiency until I started dosing it. This is not conclusive of course. Also...I can add nitrate at any level to that tank and then run a nitrate test. Either API or LaMotte and the result comes back about right after 1 hour of letting the water stir etc.

Signs of deficiency are good enough for me. That's also why this whole concept is probably a bad idea for planted tanks in general.

So the tests go back down to zero within an hour of adding the ferts?

Not sure exactly what you mean but I also suspect the carbon compounds int he wood might be important. The whole reason why nitrate gets consumed is for respiration when no O2 is around. The reason for respiration is carbon consumption. The would is breaking down after all.

I think that decomposition products are a major source of carbon in 'natural' tank, but I read that a long time ago. That being said, sacrificing nitrogen for carbon is not a good trade for planted tanks.

I am wondering if it is a surface area issue. Perhaps also a rate of water soaking in and out/surface issue.

Maybe. But I also doubt that it would be anoxic under only an inch or so of sand at the surface.

When I disturb the soil I definitely smell the sulfur. Also....there are many possible electron carrier reactions for bacterial respiration. I think at least 8. They go in order...O2, then NO3,...something something... Sulfur is in there somewhere. Walstad talks about them in her book. Has them all ranked etc. The formulas are all there.

At one point in time I had a copy of Walstad's book. I should try to dig it out at some point. I would think that redox potentials would be a good proxy to this, and it agrees with O > N > S, but you would still expect all to be present to some extent. That fact that your tank had egg farts intrigues me though, and lends some credence to the whole nitrification theory.


I really do wish I the room/capacity to investigate it more though. That being said, I'm not sure how useful it is. The idea of zero nitrates is kind of a fantasy in FW, the 'ideal' but not necessary. Most of our fish can tolerate at least up to 20 ppm without problem, unlike SW where 0 nitrates is almost required for some species. In planted tanks, 0 nitrates would be catastrophic with anything beyond medium light due to blue-green algae.

 

[jarrod0987]

Forum mechanics make it super annoying to try to break apart a quote and respond to multiple q's etc. I guess I am just burned out dealing with it.

I apologies, I was unclear about the whole tanins bacteria thing.

What happens when I submerge new soil or wood is that after a few days the tannins start leaching out. after a week to 2 weeks the denitrification kicks in.

When I first set up the 5 gal experiment with soil only and wood I did not add aeration. After a few weeks, no tanins were released at all. I was surprised by this. I always thought they were just dissolved by the water and eventually diffused out. Clearly, if aeration is a requirement then it is bacterial action that releases them. It was not really related to the other issues. I don't even know now why I mentioned it LOL.

I do understand about how valuable documenting this kind of research and debate is. I tried that a year ago when I started. I left because the reception then was very different then yours now. I found another place to document and discuss. I don't want to revisit that can of worms.It's been a long year and my journey on this subject has come to an end. I am moving into no n aquarium hobbies for a while. I need break. I am offering to share my results and discuss things with people such as yourself before I go.

As far as the autopsy goes..I know about how much wood there was. It was a lot. The effect has slowed down a lot now. When I remove the soil I can see if the wood is mostly gone. If they are not gone that gives credit to the sequestering of nitrates theory. If they are gone then the sequestering theory would not be the cause. Even if the wood only held the nitrates, they would have to come back when the wood left. The other reason I theorize carbon may play a role.

1. We have tried to use chemically inert, no carbon, porous media to try to achieve this in the past and not had any where near this strong of an effect if any.
2. The advent of carbon dosing in the marine side of the hobby has clearly demonstrated that giving the bacteria carbon to eat has a drastic effect on the amount of nitrate.

Regarding the rate....I intentionally added a dosages of nitrates that lasted about 1-2 days. Of course trying to use nitrate test kits to calculate the amount consumed is not super accurate but in some cases I was able to remove around 4 ppm of nitrate from a tank with no fish in 24 hours. I also notice that the lower the amount of nitrate gets the slower it is removed. This makes me think it is a diffusion issue. I kept all that data of course. Some of it I ran with a La Motte Nitrate kit which is very nice quality.


When it comes to 0 nitrates....0 detectable nitrates is not a fantasy. I did it all year long in multiple tanks. However...I have found algae does not die until it is well below 0.01 ppm. Not really possible to do with fish in system IMO.

It had no real value. I did not see the effect that we do in SW ULR systems. That was disappointing.

In algae ULR experiments I ran...I documented what happens with various levels of N and P under the same light. N of undetectable to say 10 ppm was about the same. Meh...Was exciting for me to try.

 

[jarrod0987]

I also forgot to add. People love there planted tanks around here. So do I. Not all FW tanks have plants.

My initial thoughts were that this would be bad for planted tanks. Why would I want to take away nitrates when plants need them etc. It would be much nicer for Fish Only tanks that have a nitrate issue such as Cichlid tanks.

However, after a year of keeping a 20 gal planted I love this. Instead of constant large WC to try to keep the nitrates down to 10 ppm ish, instead I add tiny daily doses of Potassium Nitrate which has the added benefit of adding K back in. So easy for me to set exactly the N level I want this way. SO much easier the the war of WC which I still do but seems less critical now.

 

[Caliban07]

I had two Walstad tanks that bombed out on several occasions. There could have been many reasons for this.

Carbon is only a major source of nitrogen in 'natural tanks if you have sufficient oxygen. Walstad tanks are generally low in oxygen. Surface agitation is discouraged as to sequester valuable carbon but it's a double edged sword.

My 5 gallon shrimp/Betta tank was a disaster. Both shrimp and Betta died. I had little flow or surface agitation. Next to no flow at times. The shrimp disappeared and my Betta would spend the majority of his time gulping air from the surface. Eventually after wallowing in the surface biofilm for too long he got fin rot and died. My hypothesis is that the tank lacked oxygen due to the biological oxygen demand. When things become stagnant anaerobic processes ensue which is bad for the ecosystem. This tank had no nitrates but a very large Amazon sword plant that took up a third of the tank and had access to atmosphere via its leaves. All other plant species died.

At the same time I had set up my 46 litre walstad. I have a thread if interested. Similar things would happen. My nitrates initially went through the roof and I was doing daily water changes to bring it down. This was because I had used an established filter media. I'm not overly concerned with high nitrates as I haven't seen enough, if any evidence that low amounts <100ppm have any effect on our freshwater species. I would lose a fish every week. Plants bombed out and several times I restocked them. The substrate was around 3.5 inches soil capped with gravel (total depth). Again I blame poor flow and oxygen. I never saw any denitrification in this tank. This doesn't mean that it wasn't going on. The BOD must have been huge in this tank. I never smelled any nasties. Eventually I turned to easycarbo. Plant growth took off. My phosphate and nitrate fell to zero not long after and leaves began to show signs of phosphate deficiency (green spot algae) I had to start EI to compensate and now injected co2. Plants provide massive amounts of oxygen and are your best form of nitrate removal in freshwater tanks. People have overdosed nitrate levels 10x by mistake for weeks before realising their calculations were wrong (ukaps) and there was no ill effect to the inhabitants. In my opinion, healthy plants are the key to solving algae problems. They need enough of all the important aspects that they require to photosynthesis healthily. Low Carbon is the biggest plant killer and is not talked about nearly enough.

Walstad recently acknowledged that this method of keeping plants is flawed by lack of oxygen.

I'm glad you didn't have any fish in this tank Jarrod. I made a mistake that cost the life of my fishes.


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[aqua_chem]

That's an interesting thought. 'The wood is in an anoxic environment because there's not really any oxygen anywhere'. Heh.

I think what Walstad walked back on specifically, if I remember, was the idea of not needing a filter or having minimal filtration. I think she now recommends adding some sort of filter to the system for the reasons you mentioned.

 

[jarrod0987]

I had two Walstad tanks that bombed out on several occasions. There could have been many reasons for this.

Carbon is only a major source of nitrogen in 'natural tanks if you have sufficient oxygen. Walstad tanks are generally low in oxygen. Surface agitation is discouraged as to sequester valuable carbon but it's a double edged sword.

My 5 gallon shrimp/Betta tank was a disaster. Both shrimp and Betta died. I had little flow or surface agitation. Next to no flow at times. The shrimp disappeared and my Betta would spend the majority of his time gulping air from the surface. Eventually after wallowing in the surface biofilm for too long he got fin rot and died. My hypothesis is that the tank lacked oxygen due to the biological oxygen demand. When things become stagnant anaerobic processes ensue which is bad for the ecosystem. This tank had no nitrates but a very large Amazon sword plant that took up a third of the tank and had access to atmosphere via its leaves. All other plant species died.

At the same time I had set up my 46 litre walstad. I have a thread if interested. Similar things would happen. My nitrates initially went through the roof and I was doing daily water changes to bring it down. This was because I had used an established filter media. I'm not overly concerned with high nitrates as I haven't seen enough, if any evidence that low amounts <100ppm have any effect on our freshwater species. I would lose a fish every week. Plants bombed out and several times I restocked them. The substrate was around 3.5 inches soil capped with gravel (total depth). Again I blame poor flow and oxygen. I never saw any denitrification in this tank. This doesn't mean that it wasn't going on. The BOD must have been huge in this tank. I never smelled any nasties. Eventually I turned to easycarbo. Plant growth took off. My phosphate and nitrate fell to zero not long after and leaves began to show signs of phosphate deficiency (green spot algae) I had to start EI to compensate and now injected co2. Plants provide massive amounts of oxygen and are your best form of nitrate removal in freshwater tanks. People have overdosed nitrate levels 10x by mistake for weeks before realising their calculations were wrong (ukaps) and there was no ill effect to the inhabitants. In my opinion, healthy plants are the key to solving algae problems. They need enough of all the important aspects that they require to photosynthesis healthily. Low Carbon is the biggest plant killer and is not talked about nearly enough.

Walstad recently acknowledged that this method of keeping plants is flawed by lack of oxygen.

I'm glad you didn't have any fish in this tank Jarrod. I made a mistake that cost the life of my fishes.


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Having similar issues. A few months back I added much more aeration because I had been playing around with my oxygen meter and this tank was passing but just barley.

I also see a huge plant decline since I stopped excel a few months back. Lot's of leaves with big holes and necrosis now.

 

[jarrod0987]

That's an interesting thought. 'The wood is in an anoxic environment because there's not really any oxygen anywhere'. Heh.

I think what Walstad walked back on specifically, if I remember, was the idea of not needing a filter or having minimal filtration. I think she now recommends adding some sort of filter to the system for the reasons you mentioned.

I bought one of those Hanna Ammonia LR checkers. Both tanks I had at the time were substrate only filtration. No separate filter. One had detectable ammonia but scary low Oxygen. (I have an Pinpoint II Oxygen Meter). The other had passable O2 but 0.04 ppm Ammonia. I added the power filter with bio media and that fixes it. Had no other noticeable effects but I think those 2 are important.

 

[Caliban07]

Having similar issues. A few months back I added much more aeration because I had been playing around with my oxygen meter and this tank was passing but just barley.



I also see a huge plant decline since I stopped excel a few months back. Lot's of leaves with big holes and necrosis now.

Man I need a redox meter! I just wonder if in low o2 environments nitrification slows down which may explain low nitrates? Especially with plant mass extracting it at the same time. This could be dumb logic though.

Edit: yes holes and necrosis sure does sound like carbon deficiency.

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[jarrod0987]

I tried a redox meter once. There are so many things that can effect it I did not find it so useful. I prefer an oxygen meter these days. I did notice after adding a lot of nitrate the rate it was removed slowed down the closer the level got to 0 ppm. I assumed it was a diffusion issue. However, A few days later I found out the tank had very low o2. No livestock in it so no problem but may have been the cause also. Never got back to that investigation.