# oxygen levels in planted tanks



## littletim (Apr 26, 2012)

I've set up a 10 gallon that I plan on putting a lot of medium to fast growing stem plants in, I have medium-high lighting and will be using diy co2.

The filter I'm using is a marina slim s10 hob that says on the box is up for 10 gallons, but after noticing there is almost no water movement I looked online and its flowrate is 55 gph. I plan on having this tank slightly overstocked, knowing that plants still use oxygen at night makes me worried that my water won't have enough oxygen. Is this is a legitimate concern? I thought about adding an airstone on a timre but theres already a bunch of wires and equipment crowding the tank and all of the air pumps i have are loud as hell. 

The other thing i was worried about is the co2 at night, I've read that you can leave it how it is but I my water is acidic enough without it and I dont recall how soft it is but I know it is soft. I was also wondering if co2 could displace oxygen somehow?


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## Qwedfg (Mar 7, 2012)

Co2 does not replace o2 in high enough concentrations it inhibits oxygen intake by cells I would go with toms canister filter for a 10 gal


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## BBradbury (Nov 8, 2010)

*Oxygen Levels*



littletim said:


> I've set up a 10 gallon that I plan on putting a lot of medium to fast growing stem plants in, I have medium-high lighting and will be using diy co2.
> 
> The filter I'm using is a marina slim s10 hob that says on the box is up for 10 gallons, but after noticing there is almost no water movement I looked online and its flowrate is 55 gph. I plan on having this tank slightly overstocked, knowing that plants still use oxygen at night makes me worried that my water won't have enough oxygen. Is this is a legitimate concern? I thought about adding an airstone on a timre but theres already a bunch of wires and equipment crowding the tank and all of the air pumps i have are loud as hell.
> 
> The other thing i was worried about is the co2 at night, I've read that you can leave it how it is but I my water is acidic enough without it and I dont recall how soft it is but I know it is soft. I was also wondering if co2 could displace oxygen somehow?


Hello little...

Keeping a healthy level of oxygen in such a small tank is going to be a challenge. There just isn't enough surface area to get oxygen into the tank water and carbon dioxide out of it (gas exchange).

Another issue you have with a small tank, is keeping the water chemistry stable enough for your fish. There's not enough water in such a small tank to do an effective job of diluting the ammonia and nitrites produced by the fish. 

Even having a few fish in a small tank will require you to change out half the tank water every two to three days. More often until you get some plants going.

I'd suggest getting at least a 20 gallon tank for the sake of your fish. They need room to swim. I started with a 30 gallon and because there was so much more water to cover up my early mistakes in tank management, I killed a lot fewer fish.

Just a couple of thoughts.

B


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## Kathyy (Feb 22, 2010)

Agree, CO2 doesn't displace O2. Set up the HOB filter so its outflow makes a ripple on the surface of the water to allow for gas exchange and you should be fine.

An easy way to diffuse and control DIY CO2 is to put the bottle's output in the intake of a powerhead placed low in the tank under the HOB filter's waterfall. The tiny bubbles will float in the output of the filter throughout the tank. Then put that powerhead on a timer so it turns off at night so the large CO2 bubbles will float to the top of the tank without much diffusion.


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## somewhatshocked (Aug 8, 2011)

Some counter points:

It is not difficult to keep healthy oxygen levels in a small tank. Hundreds of us on this forum do so all the time. There's plenty of surface area for gas exchange - even in a 2.5gal tank.

If you take good care of your tank, water chemistry and stability will not be an issue. Changing 50% of your water every two or three days is not necessary in a planted tank unless you're heavily dosing via EI - and then, once a week is plenty.

Depending upon the fish you plan to house, overstocking is relative and up for debate. What sort of livestock are you planning on? Some fish have such a low bioload that I've seen shrimp and snails produce more waste.


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## HD Blazingwolf (May 12, 2011)

WELL,, as some ave mentioned. u need more flow

EXCELLENT surface agitation to keep oxygen levels good

and change water weelky. u'll be fine


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## Chlorophile (Aug 2, 2011)

Yea I would disagree on the need for a larger tank. 

A small tank is easily doable with good filtration. 
Loads of us do it.
Of course, there are certain fish that would want a bigger tank, and it may be a good idea to get one, but not for the reasons stated above. 
You will be fine with water changes weekly, bi-monthly, whatever, depending on your set up.

edit: with research and preparation you don't have to kill ANY fish.


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## somewhatshocked (Aug 8, 2011)

+1 on water changes depending on setup. 

I've got a couple planted tanks that require about 15ish % be changed every 3 weeks. Some have to be changed at 50% every week like clockwork.


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## littletim (Apr 26, 2012)

I plan on keeping 3 eight banded glass barbs (lfs only has 3 left and theyre hard to find), at least 7 blue king keeri tetra, and 1 or 2 otos. if everything goes alright i was hoping on adding like 3 or 4 ghost shrimp to help the otos. I am not concerned so much about nitrogen waste as I am the ph and oxygen levels, I'm using plain gravel and flourish comprehensive so I need all the macronutrients I can get.

as far as increasing oxgenation I was thinking that maybe i could fold a piece of cloth and stick it between the lip of the hob and the rim of the tank so there would be a little waterfall, I'm not sure if that'll actually do anything but it would make me feel a lot better


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## HD Blazingwolf (May 12, 2011)

waterfall will do quite a bit for oxygen. it will splash the surface and it will increase surface of water to air contac time


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## s_s (Feb 15, 2012)

somewhatshocked said:


> Some counter points:
> 
> It is not difficult to keep healthy oxygen levels in a small tank. Hundreds of us on this forum do so all the time. There's plenty of surface area for gas exchange - even in a 2.5gal tank.


Oxygen levels generally are not a problem in the common, rectangular shaped tanks, regardless of size. It does become a problem for column and many hex tanks. 

It's all about the ratio of surface area to tank volume. A ratio, of course, scales.


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## HD Blazingwolf (May 12, 2011)

s_s said:


> Oxygen levels generally are not a problem in the common, rectangular shaped tanks, regardless of size. It does become a problem for column and many hex tanks.
> 
> It's all about the ratio of surface area to tank volume. A ratio, of course, scales.


says who?

good water movement helps as well. surface agitation adds more oxygen because it adds exactly what u said. more surface area
what type of filtration? how many plants? how many fish?
do you overfeed? do you want less water chagnes?

oxygen is the main key ingredient for healthy bio filtration which is all any tank really needs.. the more oxygen u have, the more efficient it is and the less your livestock are stressed by overfeeding or less frequent water chagnes


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## andkoni (Nov 6, 2005)

Any new information about importance of oxygen for plants ?


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## tylergvolk (Jun 17, 2012)




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