# several questions after reading Ecology of the planted aquarium



## Minipol (Jul 4, 2006)

Well, i'm not quite finished yet (p 153) 
So far, i've got a number of questions:

1. In natural lakes, C02 is almost depleted at noon, it then replenishes.
Would it be good to simulate co2 take up in the morning and then lower light again after say, the first 4 hours when C02 is taken up?
I could cut 1 or 2 of my 4 TL's put i'm not sure if the effect would be good on plants or even necessary. Just seemed like an interesting thing to know.

2. Is a tiger lotus good for aerial advantage? Or do the broad leaves cause more havoc than good because they tend to shade the other plants?

3. Echinodorus that grow well seem to have a high turnover of leaves. Do you cut them or leave them in? What with dying leaves that have brush algae on them?

4. There is talk about how lilies releases CO2 into the air. Can the emergent
growth of hydrilla takes advantage of the CO2 that is left over from the lillie?


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## sb483 (May 29, 2006)

It's a free forum; just ignore me while I amuse myself (of course you - just as I & everyone else - are more interested in what *dwalstad *has to say):


Minipol said:


> 1. In natural lakes, C02 is almost depleted at noon, it then replenishes.
> Would it be good to simulate co2 take up in the morning and then lower light again after say, the first 4 hours when C02 is taken up?
> I could cut 1 or 2 of my 4 TL's put i'm not sure if the effect would be good on plants or even necessary. Just seemed like an interesting thing to know.


CO2 gets depleted because the plants use it up. If you have growing plants, this should simulate the CO2 uptake just fine, without controlling any light levels. Lowering light doesn't seem like a simulation of any natural process, and it doesn't sound like it would do much good.



Minipol said:


> 2. Is a tiger lotus good for aerial advantage? Or do the broad leaves cause more havoc than good because they tend to shade the other plants?


The plants they shade are most likely non-emergent plants, which don't need all that much light anyway (from the book, submerged plants are basically shade plants). Extra light only contributes to algae, so the floating leaves reduce excess light which submerged plants don't need and which algae can grow from (too much light causes iron photoreduction which provides algae with more iron, from the book).



Minipol said:


> 3. Echinodorus that grow well seem to have a high turnover of leaves. Do you cut them or leave them in? What with dying leaves that have brush algae on them?


In the last chapter, I think, she discusses pruning the leaves regularly for continuous plant growth and nutrient uptake.



Minipol said:


> 4. There is talk about how lilies releases CO2 into the air. Can the emergent
> growth of hydrilla takes advantage of the CO2 that is left over from the lillie?


The lily itself can take advantage from the CO2 it releases, so other emergent plants should be able to.

When *dwalstad *replies with the _real _answers, I'll find out how I scored


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## Minipol (Jul 4, 2006)

Hehe, your answers helped already and make sense so your score will probably be high


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## flagg (Nov 29, 2004)

Minipol said:


> Well, i'm not quite finished yet (p 153)
> So far, i've got a number of questions:
> 
> 2. Is a tiger lotus good for aerial advantage? Or do the broad leaves cause more havoc than good because they tend to shade the other plants?


Tiger lotuses make an excellent addition to the NPT. If the tank is in front of a window, I wouldn't worry about other plants being shaded out. However, if it were to become a problem, you could always prune the leaves.



Minipol said:


> 3. Echinodorus that grow well seem to have a high turnover of leaves. Do you cut them or leave them in? What with dying leaves that have brush algae on them?


They should be left in the tank in order to help build up mulm and feed the plants in the long run.



Minipol said:


> 4. There is talk about how lilies releases CO2 into the air. Can the emergent
> growth of hydrilla takes advantage of the CO2 that is left over from the lillie?


I would imagine that any CO2 that is released into the air would dissipate into the atmosphere and be no more available to plants than O2 that plants release into the air would be available for us to breathe.

-ricardo


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## Minipol (Jul 4, 2006)

I thought it might be better to leave the leaves in.
However, big swords have a high turnover rate so maybe a lot of mulm will be formed?

As for the CO2, the cover prevents good circulation of air so i thought that the CO2 level in the air under the cover might be higher than the air outside the cover. Then emergent plants should be able to use the air C02?


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## dwalstad (Apr 14, 2006)

Minipol said:


> I thought it might be better to leave the leaves in.
> However, big swords have a high turnover rate so maybe a lot of mulm will be formed?
> 
> As for the CO2, the cover prevents good circulation of air so i thought that the CO2 level in the air under the cover might be higher than the air outside the cover. Then emergent plants should be able to use the air C02?


You have described two situations where you do, indeed, have competing factors. Thus, without actually doing a comparative experiment, your guess is as good as mine. The choice is yours.

I think SB483 gets an A+!


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## Minipol (Jul 4, 2006)

It would be interesting to know if other emergent plants could use the lilies produced CO2. It all depends off course on how much of the CO2 would be around under the hood. If there is no hood or one which isn't isolated, then i guess no extra CO2 would be avaible to the other emergent plants.


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## sb483 (May 29, 2006)

:bounce: :bounce:

When I kept amazon swords, I had to prune them regularly to keep them from overcrowding. On sunny days the tank received direct sunlight from morning to late afternoon, and there was no water movement - with the potting soil layer, I'd say growing conditions were close to ideal. Those things get huge! During a month when I forgot to prune them, the upper leaves were fighting for light on top, and the whole tank was dark and unsightly (despite being next to a window:!: ) as the lower leaves were decaying away.

I'd recommend pruning the amazons, at least before they start making the bottom of the tank so dark you can see outside reflections instead of the bottom surface.


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## Minipol (Jul 4, 2006)

Okay thanks for the info. In the 500l tank i've got 2 and in the 300l upstairs i've got 2 also but one has many planlets. I guess there's about 20 or 30 small ones.
Tank only has 2 lights so i was surprised to see it producing plantlets.

Unfortunately, i won't be able to plant more as 2 amazons seem enough for a tank. I wonder if you could set up a planted aquarium just with amazon, but then off course more than one of them.

I'll make sure to prune them. Normally i cut off the unhealthy leaves that are decaying. So do you prune the healthier leaves too when they get to big?


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## sb483 (May 29, 2006)

Minipol said:


> Unfortunately, i won't be able to plant more as 2 amazons seem enough for a tank. I wonder if you could set up a planted aquarium just with amazon, but then off course more than one of them.
> 
> I'll make sure to prune them. Normally i cut off the unhealthy leaves that are decaying. So do you prune the healthier leaves too when they get to big?


Healthy amazon swordplants are hardy and robust, they can even stand overpruning. With a tank full of giant swordplants, you stop caring much for individual specimens - I once pruned one that was blocking all the light down to 4 leaves; it survived, and in a month needed pruning again like all the others.

You don't have to prune, *Minipol*; when the swordplant starts growing too large (which, given light & soil is almost certain) you'll know when it's time to trim the older leaves.


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## flagg (Nov 29, 2004)

Minipol said:


> It would be interesting to know if other emergent plants could use the lilies produced CO2. It all depends off course on how much of the CO2 would be around under the hood. If there is no hood or one which isn't isolated, then i guess no extra CO2 would be avaible to the other emergent plants.


Since all molecules move down the concentration gradient, whatever CO2 escapes to the area above the tank (an area, we'd have to assume has a high concentration of CO2) is going to start spreading into the atmosphere of the room (area of low CO2 concentration.) The only way to stop this is to cover the tank with an airtight lid. Barring that, the CO2 will not remain above the tank indefinetly. It will find a way out and the looser fitting the tank, the more quickly this will happen. So really, the question is how fast is the CO2 going to diffuse into the atmosphere? I would imagine, using a typical hood, that it would be rather quickly and that there wouldn't THAT much of a benefit to other emergent plants.

Something to also consider: let's assume that the CO2 hangs around long enough to be used up by other emergent plants. Well, BOTH the other emergent plants AND the lillies will begin using up the CO2 at the same time (ie, during photosynthesis) So, if the CO2 hangs long enough, will the lillies use it up faster, slower or at the same rate as other plants? If lillies give off a lot of CO2 then I think they probably also consume a lot of CO2. This would make sense considering their fast rate of growth. Now, if the lillies consume CO2 faster than other emergent plants the REAL question is: could the lillies us the CO2 produced by the hydrillas?


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## dwalstad (Apr 14, 2006)

flagg said:


> If lillies give off a lot of CO2 then I think they probably also consume a lot of CO2. This would make sense considering their fast rate of growth. QUOTE]
> 
> I predict that lillies quickly consume all available CO2.


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