Plant Problems

[anewbie]

There is no doubting that Excel kills algae, at least sometimes. But that alone should cause us to never use it in a tank with fish. It contains a derivative of glutaraldehyde, a highly toxic disinfectant. Used at recommended dosage, Vallisneria plants will usually be killed, along with some other plants. Some bacteria can be harmed--glutaraldehyde is after all used in ship ballasts to kill bacteria. And in hospitals to sterilize medical instruments. I would never use this in an aquarium with fish.

Before i understood what the stuff was I used it in a tank with Jungle val (not sure of the exact species of Vallisneria); the plant i had was particularly hearty and it might have suppress it a little but not enough to notice. The stuff still grows excessive.

 

[anewbie]

Assuming most of us have a decent number of fish in an aquarium, yes, with a natural or low-tech method planted tank there will without question always be sufficient ammonia. In most situations, the CO2 will be the limiting factor. It was for me. I do not believe in supplementing CO2 in any form because this too does harm the fish over time, that is now accepted. So I relied solely on the natural CO2. Once you get into a high-tech system, the ammonia will be used up, though it depends upon the plant load and fish load, and the other factors like light, CO2, nutrient dosing. Nitrate is commonly added, but the plants have to use considerable energy converting it back into ammonium in order to use it.

Can you expand on this with regards to co2 being bad for fishes. I had intended to dose it in the aquarium i'm setting up next year at a modest level to ehance the growth of the plants. I do use it now with my angles and festum again at a modest level. If it is bad for the fishes i can change that aspect for the 550 i'm setting up; but i would like more details. I do not consider domestic angels as a particularly sensitive fish but i will be stocking more exoctic species like geo (probably winemilleri) and taeniacara candidi (these will be in the low ph tank which would not have co2 injected anyway) and would like a better understanding of how co2 impact fishes and if that is uniform issue or if modest dosage is ok.

 

[Byron]

Can you expand on this with regards to co2 being bad for fishes. I had intended to dose it in the aquarium i'm setting up next year at a modest level to ehance the growth of the plants. I do use it now with my angles and festum again at a modest level. If it is bad for the fishes i can change that aspect for the 550 i'm setting up; but i would like more details. I do not consider domestic angels as a particularly sensitive fish but i will be stocking more exoctic species like geo (probably winemilleri) and taeniacara candidi (these will be in the low ph tank which would not have co2 injected anyway) and would like a better understanding of how co2 impact fishes and if that is uniform issue or if modest dosage is ok.

There was an article on this in PFK about three or four years ago. I can't find it now, you may have better luck. It pointed out that new research indicates that diffused CO2 has more of an effect on fish than many believe. I have had issues just with the natural CO2 occurring during darkness with my Corydoras, and solved it by increasing the surface disturbance. I am not going to subject my fish to any more.

Studies showing a detrimental effect on fishes from elevated CO2 levels are instructive.

Acid-base physiology and CO2 homeostasis: Regulation and compensation in response to elevated environmental CO2

Acid-base balance is one of the most tightly regulated physiological processes. Accumulation of metabolic CO2 produced at the tissues causes extra- or…

www.sciencedirect.com

https://agupubs.onlinelibrary.wiley.com/doi/pdfdirect/10.1029/2004JC002564

 

[CarissaT]

Can you expand on this with regards to co2 being bad for fishes. I had intended to dose it in the aquarium i'm setting up next year at a modest level to ehance the growth of the plants. I do use it now with my angles and festum again at a modest level. If it is bad for the fishes i can change that aspect for the 550 i'm setting up; but i would like more details. I do not consider domestic angels as a particularly sensitive fish but i will be stocking more exoctic species like geo (probably winemilleri) and taeniacara candidi (these will be in the low ph tank which would not have co2 injected anyway) and would like a better understanding of how co2 impact fishes and if that is uniform issue or if modest dosage is ok.

I’m sure having co2 at 10x the level it normally would be no doubt puts the fish under at least some small amount of stress to adapt, however at the same time having plants that are growing fast and well will reduce ammonia and nitrates faster, so maybe there’s a trade off there that’s worthwhile to the fish.

 

[Colin_T]

I’m sure having co2 at 10x the level it normally would be no doubt puts the fish under at least some small amount of stress to adapt, however at the same time having plants that are growing fast and well will reduce ammonia and nitrates faster, so maybe there’s a trade off there that’s worthwhile to the fish.

There has been research done on terrestrial plants getting double the carbon dioxide (CO2) that is currently in the atmosphere and it showed a negative affect on the plants. The research was done by scientists who are trying to see if any plants will survive in the future when CO2 levels are higher than today. The results were not good and even though they were terrestrial plants, a similar conclusion can probably be put to aquatic plants.

Excess CO2 will also drop the pH and that can affect shrimp, snails and fish that don't like acid water.

 

[Byron]

I’m sure having co2 at 10x the level it normally would be no doubt puts the fish under at least some small amount of stress to adapt, however at the same time having plants that are growing fast and well will reduce ammonia and nitrates faster, so maybe there’s a trade off there that’s worthwhile to the fish.

I'm not just "arguing" with you, I hope you realize that, because you are raising very creditable issues but where's there's evidence to refute something it is necessary to put it out there.

Aquatic plants will rapidly take up ammonia. You will never be able to have ammonia above zero with our basic (but reliable) test kits any more than with bacteria doing the ammonia oxidation. And with plants there is no nitrite or nitrate resulting. These benefits exist in any balanced natural (low-tech) planted tank. Getting the plants growing faster by using diffused CO2 is not going to increase these benefits. But there are real serious detriments. In order for added CO2 to benefit, the light has to be more intense than it would otherwise, and this is a serious issue for many forest fish--cardinal tetras for example have what Baensch & Rhiel termed a light phobia. Also, the other nutrients have to be increased as well, to maintain the light/nutrient balance, or the CO2 will just cause problem algae, and this is not going to benefit fish, especially soft water species, quite the reverse. So adding the CO2 not only causes harm on its own, but the accompanying necessary increases in light and fertilizers have additional harm.

As for the CO2, it is a delicate balance easily tipped. I noticed the Corydoras in my 70g tank with plants were respirating very heavily in the morning, but not after a few hours. It was the additional CO2 created at night that caused it. I increased the surface disturbance and it went away, and ever since the respiration has been normal in the morning or any time. It does not take much.

Stress takes a toll on fish, slowly and unseen but still the damage is being done. We must never do anything that increases stress just to have whatever for our own benefit.

Many who run high-tech planted tanks have few or even no fish in the tanks. There is considerable wisdom in that.

 

[CarissaT]

There has been research done on terrestrial plants getting double the carbon dioxide (CO2) that is currently in the atmosphere and it showed a negative affect on the plants. The research was done by scientists who are trying to see if any plants will survive in the future when CO2 levels are higher than today. The results were not good and even though they were terrestrial plants, a similar conclusion can probably be put to aquatic plants.

Excess CO2 will also drop the pH and that can affect shrimp, snails and fish that don't like acid water.

There‘s little doubt that adding co2 increases the growth rate in aquatic plants dramatically. Whether that‘s considered a positive or negative effect, is up to the one who is growing them. The air naturally has about 400ppm of co2, water in our tanks that is in equilibrium with the air has about 2-3ppm. That is why many plants naturally grow emersed, to obtain more co2 from the air than they can get from the water. It’s interesting that studies show that terrestrial plants are increasing their growth to try to keep up with the additional co2 humans are producing.

It’s true that adding co2 creates carbonic acid which of course lowers ph at a set ratio, e.g. increasing co2 x amount will decrease ph x amount and assuming you know the Kh of the water you can calculate those numbers, that’s how a drop checker works (and assuming you haven’t added additional buffers other than KH, such as phosphate buffers, which will change that calculation). However, what most fish or other aquatic creatures actually are the most sensitive to are KH swings, not pH. Under most circumstances in our aquariums, a pH change will actually signify a KH change, which is what actually stresses the fish because of their osmotic regulation. It’s not the pH itself that is usually the issue, that’s just the end result of a high or low KH. But because pH is so easy to test for, that’s what people talk about. In a co2 injected tank, because the KH is not affected by co2, the fish generally don’t even notice fluctuating pH levels. So for example, if you take fish who like “hard” water (generally meaning a high KH/pH as well as high levels of other dissolved elements, GH etc) and put them in a tank with naturally “soft” water (low KH, GH, etc which will also have low pH) that is not going to be good for them. But if you take the fish in that ”hard” water and then inject co2 into that same water, you are not changing the fact that it’s “hard” water even though the pH will drop 10 fold. So the pH level really ceases to matter, for most intents and purposes.

 

[CarissaT]

I'm not just "arguing" with you, I hope you realize that, because you are raising very creditable issues but where's there's evidence to refute something it is necessary to put it out there.

Aquatic plants will rapidly take up ammonia. You will never be able to have ammonia above zero with our basic (but reliable) test kits any more than with bacteria doing the ammonia oxidation. And with plants there is no nitrite or nitrate resulting. These benefits exist in any balanced natural (low-tech) planted tank. Getting the plants growing faster by using diffused CO2 is not going to increase these benefits. But there are real serious detriments. In order for added CO2 to benefit, the light has to be more intense than it would otherwise, and this is a serious issue for many forest fish--cardinal tetras for example have what Baensch & Rhiel termed a light phobia. Also, the other nutrients have to be increased as well, to maintain the light/nutrient balance, or the CO2 will just cause problem algae, and this is not going to benefit fish, especially soft water species, quite the reverse. So adding the CO2 not only causes harm on its own, but the accompanying necessary increases in light and fertilizers have additional harm.

As for the CO2, it is a delicate balance easily tipped. I noticed the Corydoras in my 70g tank with plants were respirating very heavily in the morning, but not after a few hours. It was the additional CO2 created at night that caused it. I increased the surface disturbance and it went away, and ever since the respiration has been normal in the morning or any time. It does not take much.

Stress takes a toll on fish, slowly and unseen but still the damage is being done. We must never do anything that increases stress just to have whatever for our own benefit.

Many who run high-tech planted tanks have few or even no fish in the tanks. There is considerable wisdom in that.

Totally understood. Adding co2 inserts an additional risk factor and potential stress to the fish, I don’t disagree. Besides possible stresses with additional light and fertilization, you also have the risk that something will go wrong with the system and it will inject too much co2 and quickly start suffocating the fish. Does that mean nobody should ever do it?

Maybe some would feel that’s the case, and they are entitled to their opinion, but if you follow that logic, should nobody ever keep fish that aren’t suited to their water chemistry perfectly? What about feeding fish flake food instead of buying frozen or fresh that are ideal for that particular species? What about using plastic plants instead of real plants? Using fish to cycle a tank? Keeping wild caught fish who would have otherwise been able to live out their life not in a small glass box for our enjoyment? Using heaters which can potentially malfunction and kill off a tank of fish in a few hours? My point simply being that there are a lot of risks and a lot of issues involved in all aspects of this hobby. If someone has the position that we should avoid any and all unnecessary potential stresses to fish, then really the ethics of keeping fish at all has to come into question.

In real life, people are setting up tanks and buying fish every day who don’t even understand the nitrogen cycle and know nothing about the fish they are keeping, the quality of their water, or much of anything else. In fact I would say more often than not, on average people who buy fish make them subject to these major issues which most definitely stress and kill fish. Then they think they just got a disease, and go out and buy more. Worrying about the stress of something like co2 injection, which when done properly produces no visible negative effects on the fish 99% of the time, is so minor as to be not worth talking about.

For your corydoras to be respirating heavily, I would think they must have had a lack of oxygen in the water with the plants not doing photosynthesis, which increasing circulation would fix. In a tank with co2 injection, levels are typically 20-30ppm (10x regular atmospheric equlibrium) with no respiration issues. At 40-50ppm you start running the risk of respiration issues. I can’t imagine that your Cory’s would possibly be able to produce that much co2 on their own since it takes a lot of injection to start even getting close to the level of gasping issues. One way to know, if it were to happen again, would be to test the pH In the morning and then again later in the evening, that amount of co2 would create a difference of at least 1.0.