All my fish will be dead by morning!!

[tetrakid]

I have no idea. I just did that and my fish are so happy in party mood. I suppose other seniors may have some explanation?
Maybe a "placebo effect"?

Pardon my ignorance, but why the lip needs to submerged under the water? I have kept fish with the lip above the water with no problems.

[hardric]

Ok... U just told us to do something but have no idea why???

[iggi3z]

I think 0 nitrates may mean that your cycle crashed and that your cycle restarted. Probably during ur crisis period there may be due to ammonia / nitrite levels. But I guess you changed your water rather freq and it's back to normal. Also, nv heard about having the lip touching the surface theory before. Any bros care to enlighten?

[tetrakid]

This was what I discovered in my experience. After I did that, my fish are all surviving well, but not before that. I used to let water from the filter splash on the water surface, with the idea of giving my fish more oxygen that way, but that only caused a thick layer of stuff and small tough bubbles on the surface.

Ok... U just told us to do something but have no idea why???

[iggi3z]

Hmm. I think the theory still stands that oxygenation is a function of surface agitation over an large area .Just that the definition of surface agitation not that well define.

It's an argument for breaking the surface tension of water over a large surface area.

Normal airstone have lots of bubbles. But they rise vertically hence the max surface area is that area above the airstone is less superior to having a powerhead places at the waterline

My thoughts.

[tetrakid]

I immediately concur with you on that. Such a superb revelation. I hope not many will beg to differ.

So now we know, surface agitation as such is not just a matter of moving the surface in a mechanical manner, but rather in a way that brings benefits rather than problems.

[hardric]

This was what I discovered in my experience. After I did that, my fish are all surviving well, but not before that. I used to let water from the filter splash on the water surface, with the idea of giving my fish more oxygen that way, but that only caused a thick layer of stuff and small tough bubbles on the surface.

I hope you understand the difference between a casual factor and a causal factor. Just because you stop water splashing on the water surface doesn't mean that it is the reason the fish are surviving well.
In the case of the thread starter, his nitrates are 0. That is almost not possible without using special equipment to reduce the nitrates. Therefore, his water is not cycled, not because of the water splashing.

[tetrakid]

You've understood me wrong there.

My point has nothing to do with splashing water itself. If anything, splashing water is good, as it provides agitation.

My point is more about effective oxygenation of the water. Please read the post by iggi3z above, which contains the substance of what I wanted to mean. Nitrates and other water contaminating factors are important, but my top priority is oxygen level.

I hope you understand the difference between a casual factor and a causal factor. Just because you stop water splashing on the water surface doesn't mean that it is the reason the fish are surviving well.
In the case of the thread starter, his nitrates are 0. That is almost not possible without using special equipment to reduce the nitrates. Therefore, his water is not cycled, not because of the water splashing.

[hardric]

Also, what is the filter used?

If it is the hang-on type external filter, make sure you ensure the water level is up to the 'lip' of the water outlet. The aim is that water coming out from the filter must be pushing the WATER SURFACE strongly to the rest of the tank's water surface, not just falling into the water at one spot. There should not be bubbles on the water surface but a nice clean water surface, ie no surface.

This, together with possible water contamination are the first things you should be checking and remedied. But sad to say, if fish have reached an advanced stage of illness due to unfavourable conditions, there's little else one can do.

That's exactly what you said in post #3.

If you love your fish, and want your fish to love you, always ensure the 'lip' of the filter outlet is submerged under water, not remain above it.

You may think the fish is not getting enough oxygen, but I assure you they are.

Then I asked you why the lip must be above submerged. Then you said you don't know.

I have no idea. I just did that and my fish are so happy in party mood. I suppose other seniors may have some explanation?
Maybe a "placebo effect"?

What igzz3z said didn't have anything to do with what the Thread Starter asked. Anyway, if the fish doesn't have oxygen, they would be gasping for air. Not hiding in one corner as the Thread Starter described.

[tetrakid]

What iggi3z said contains, I believe, the answer to the 'mystery', hence I said it is a superb post. It has everything to do with solving the problem and not 'nothing to do with it'. Before his post, I have had this strong inkling that the problem may have something to do with oxygen, but may be other reasons too, hence I didn't want to commit myself, so said I didn't know. But iggi3z's post regarding the theory (principle) enlightened me a lot, so I immediately concurred with him on that after reading it.

As you see, Sazeyplus2 had said he originally had his water level lower down and water had been splashing down from the filter outlet. onto the water surface and mostly falling on one spot, agitating the surface but not effectively for the purpose of good oxygenation, at best only sub-optimal oxygenation. If that was the case, then iggi3z's post provided the solution to the problem in terms of improving the oxygenation.
Hope this makes sense.

Hmm. I think the theory still stands that oxygenation is a function of surface agitation over an large area .Just that the definition of surface agitation not that well define.

It's an argument for breaking the surface tension of water over a large surface area.

Normal airstone have lots of bubbles. But they rise vertically hence the max surface area is that area above the airstone is less superior to having a powerhead places at the waterline.

My thoughts.

[hardric]

1) Fish swimming in oxygen deprived waters will gasp for air and will swim near the top of the water. Thread starter did not describe the fish behaving in that way. Please go google how fish behave when there isn't enough oxygen.
2) 4 guppies in a 10 gallon tank with 2 live plants? No oxygen problems. Cories not counted because they live in oxygen deprived waters in nature and can always swim up to breath "air". Cories are part-time air breathers
3) The Thread Starter had the tank for 3 months. If the fish did not have enough oxygen, they wouldn't live for 3 months.
That's all I have say. If you truly believe that the fish did not enough oxygen for 3 months and finally die after 3 months, then go ahead. I can't stop you.

[tetrakid]

Lol, it is obvious to me you feel strongly that the fish in that particular tank are not deprived of oxygen. But I do agree with you on most of your points, which are valid, including that the fish there are not deprived of oxygen.

Oxygen deprivation can be a sudden, or gradual affair, and even undetected by fish if it happens gradually over a period of time. Sub-optimal presence of oxygen will not affect fish drastically, but will cause side health effects, known and unknown. Among all the factors that are deterimental to fish health and aquarium health, I view oxygen as the most important, and to be treated first before anything else. An abundance of oxgen, as opposed to marginal oxygen concentration, brings much benefit to all aquarium organisms.

1) Fish swimming in oxygen deprived waters will gasp for air and will swim near the top of the water. Thread starter did not describe the fish behaving in that way. Please go google how fish behave when there isn't enough oxygen.
2) 4 guppies in a 10 gallon tank with 2 live plants? No oxygen problems. Cories not counted because they live in oxygen deprived waters in nature and can always swim up to breath "air". Cories are part-time air breathers
3) The Thread Starter had the tank for 3 months. If the fish did not have enough oxygen, they wouldn't live for 3 months.
That's all I have say. If you truly believe that the fish did not enough oxygen for 3 months and finally die after 3 months, then go ahead. I can't stop you.

[iggi3z]

Well to be honest. My reply was partially directed at TS about the 0 nitrate and his cycle crashing.

And the oxygenation explanation was to reply at the topic of the water level at the "lip". My post was not addressing the causal relationship between your hypothesis and TS situation. But I was just highlighting the concept of oxygenation as I believe. Sorry if I caused any misunderstanding. Peace!

[tetrakid]

Your post came at a time when I have just discovered the 'secret', namely effective oxygenation via the water surface. And that was why I said it is a 'superb post'. I believe there is much misunderstanding by fish hobbyists in regard to surface aeration. And that is why your post immediately struck a chord with me. I lapped up every single word in your post about surface tension. It is important to read every single word there. I am glad I did. Thank you for the knowledge.

Well to be honest. My reply was partially directed at TS about the 0 nitrate and his cycle crashing.

And the oxygenation explanation was to reply at the topic of the water level at the "lip". My post was not addressing the causal relationship between your hypothesis and TS situation. But I was just highlighting the concept of oxygenation as I believe. Sorry if I caused any misunderstanding. Peace!

[hardric]

Dear iggi3z,

I did not misunderstand anything don't worry. You already mentioned that 0 nitrates meant the cycle was not completed and therefore it was a reason for the fish to die. You only talked about oxygen levels because of the "lip" issue.

To others,
Anyway, I believe opinions in the forum should ideally be backed by evidence. I am unlikely to believe something just because a forummer posted it. There is no "secret" to effective oxygen exchange in water. All these have been documented and math formulas have already been formulated.
http://en.wikipedia.org/wiki/Aeration
http://en.wikipedia.org/wiki/Water_aeration
http://en.wikipedia.org/wiki/Surface_tension
http://en.wikipedia.org/wiki/Contact_angle

In short, the best ways of putting oxygen into water is through 1. passing liquid through air and 2. passing air through liquid. The 1st process is basically fountains, waterfall and even raindrops. The 2nd process is air stones. The bigger the surface area it hits, the better. Microbubbles are the most effective. Of course, both means that there is a breaking of surface tension.

Why having the lip submerged is not the best way of putting oxygen into the water? Because of the contact angle. To break through the surface tension, the most important is the vertical drop. The force of the vertical drop must break through force of the surface tension. If the water from the filter just smoothly flows into the water, it might not break the surface tension. Therefore, no exchange of gasses.

[felix_fx2]

The water might be a referred to as quite hard aka liquid rock.
That would be a likely cause besides Nitrogen cycle crashing.

I will rather wait for TS to reply.

[tetrakid]

First of all, I must thank both hardric and iggi3z for the valuable sight both have brought to us with regard to this very important matter of aeration in fish tanks.

With regard to the the hangon-on filter, I am now clearer on what hardric believes, namely that water coming out from the filter outlet must fall vertically onto and penetrate the water surface with some force, and not be flowing 'smoothly' into the water from sideways as is the case when the filter 'lip' is at the same level or submerged below the water. And, believe it or not, this is the interesting part.

In my experience, I have actually used both methods with the sole intention of increasing oxygenation of my tank. Whilst most hobbyists will without hesitation say that 'splashing' the water onto the surface is more effective, in practice, it really depends on the size of the tank, especially the surface area.

If the tank's surface area is small, splashing water at the surface is truly effective, since then surface agitation covers all or most of the surface. But with a bigger tank where the tank's surface covers a wide area, splashing a small stream of water at one localised spot on the side will hardly move the other parts of surface much, thus giving only minimal aeration. Considering that surface aeration is most effective if agitation is present throughout the whole water surface area, forcing the water coming out from the filter to move sideways continuosly will achieve this situation beautifully. By raising the tank's water level to the lip of the hang-on filter, a sideways flowing current is created which can be seen to move to the whole surface area of the big tank. It is this constant sideways current which produces a 'nice and clean' surface.

On the surface, some may be worried that such a 'smooth' flow of water has no aeration effect at all. But I am definitely convinced that it is the best way to use a hang-on filter effectively, as good surface agitation is continuosly present thoughout the tank's surface.

The same principle applies when using canister filters, only perhaps it does it more efficiently and powerfully than a hang-on filter.

.... Why having the lip submerged is not the best way of putting oxygen into the water? Because of the contact angle. To break through the surface tension, the most important is the vertical drop. The force of the vertical drop must break through force of the surface tension. If the water from the filter just smoothly flows into the water, it might not break the surface tension. Therefore, no exchange of gasses.

[doppelbanddwarf]

If that is the case, why do planted tank hobbyists minimise agitation of the surface to prevent loss of co2?

[hardric]

First of all, I must thank both hardric and iggi3z for the valuable sight both have brought to us with regard to this very important matter of aeration in fish tanks.

With regard to the the hangon-on filter, I am now clearer on what hardric believes, namely that water coming out from the filter outlet must fall vertically onto and penetrate the water surface with some force, and not be flowing 'smoothly' into the water from sideways as is the case when the filter 'lip' is at the same level or submerged below the water. And, believe it or not, this is the interesting part.

In my experience, I have actually used both methods with the sole intention of increasing oxygenation of my tank. Whilst most hobbyists will without hesitation say that 'splashing' the water onto the surface is more effective, in practice, it really depends on the size of the tank, especially the surface area.

If the tank's surface area is small, splashing water at the surface is truly effective, since then surface agitation covers all or most of the surface. But with a bigger tank where the tank's surface covers a wide area, splashing a small stream of water at one localised spot on the side will hardly move the other parts of surface much, thus giving only minimal aeration. Considering that surface aeration is most effective if agitation is present throughout the whole water surface area, forcing the water coming out from the filter to move sideways continuosly will achieve this situation beautifully. By raising the tank's water level to the lip of the hang-on filter, a sideways flowing current is created which can be seen to move to the whole surface area of the big tank. It is this constant sideways current which produces a 'nice and clean' surface.

On the surface, some may be worried that such a 'smooth' flow of water has no aeration effect at all. But I am definitely convinced that it is the best way to use a hang-on filter effectively, as good surface agitation is continuosly present thoughout the tank's surface.

The same principle applies when using canister filters, only perhaps it does it more efficiently and powerfully than a hang-on filter.

I didn't believe. I used scientific facts.
You can believe your theory.

[tetrakid]

I can only think of the simple answer - because CO2 is expensive.

I have not much experience with plants. But frankly speaking, even if I were to go into aquatic plants, I wil still like to ensure good surface oxidation in the manner I have mentioned earlier and leave the fish to upkeep the CO2 level. I believe a constantly well-balanced low-tech planted aquarium will be self-sustaining.

If that is the case, why do planted tank hobbyists minimise agitation of the surface to prevent loss of co2?