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People have been telling me different things about c02 and I recently watched this video and the guy said that you can have high c02 and high oxygen levels at the same time. I'm currently running a fluval diffuser at 2-3bps in my 20L. I wanna hear your thoughts on this .
 

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"High" O2 would usually involve disturbing the water quite a bit. With two HOB filters
you should have a "normal" amount of O2. So why do you want it to be higher than needed for fish to live ?
Plants take in CO2 and generate O2 as their waste product, the reverse of animals.
This comes to a stop after lights out because the growth process has stopped.
So you should stop the CO2 at dark or even just a bit before that.
The water in the tank contains a normal amount of CO2, but the plants do use it
while the light is on. So if your adding more of it and the plants no longer use it after lights out, then it will build up if you keep it running. That is what might hurt the fish.
But as long as you turn it off, it will slowly return to that normal level of it that you already have if none is being added.
Not that familiar/w the other plants but the Petchii(?) look to be less than a year old and in good health.
The Amazon looks great. I think I'd take a look at the ferts if you aren't getting the growth you expect.
 

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I suppose you could, although I'm not sure there's much benefit to that...

It's not like injecting enough O2 will make your fish immune to CO2 poisoning,
 

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I suppose you could, although I'm not sure there's much benefit to that...

It's not like injecting enough O2 will make your fish immune to CO2 poisoning,
The higher the O2 content in the water, the more CO2 the fish can tolerate. Of course water will only hold a limited amount of O2 in solution, so no obtainable amount of O2 in the water will make the fish immune to CO2.
 

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A detail that gets missed here a lot of the time:

Respiration (using O2 to break down sugars & produce energy, giving off CO2) takes place 24 hours a day. This is a process common to all living things. Plants don't stop respiring during the day.

Photosynthesis (using CO2 and light energy to produce sugars, producing oxygen) takes place only during the lighted hours, among plants only. It's just that photosynthesis tends to produce more oxygen than the individual plant needs.
 

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People have been telling me different things about c02 and I recently watched this video and the guy said that you can have high c02 and high oxygen levels at the same time. I'm currently running a fluval diffuser at 2-3bps in my 20L. I wanna hear your thoughts on this .
Technically that's correct. As you know plants use the carbon atom in co2 not oxygen atom during photosynthesis. Oxygen is a waste gas directly liberated from the co2 molecule producing two oxygen molecules. So more co2 = more oxygen. Here's a representation below of the co2 molecule.

The question you seem to be asking is. What are the limits?

Btw, your particular bubble count means nothing to anyone else. It's specific to your tank.
 

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Sorry to side track this a slight bit.

I am about to make my Rex Grigg Reactor for CO2 but then I thought about also adding a possible connection for an air pump to add o2 to the water. My thought was to have the CO2 while the plants are active (light time) and then have the air pump kick in during the non active time (dark time) to build up the oxygen in the water. I thought about also adding it during the day time but was fearful that it would inhibit the absorption of the CO2 in the water since both gasses would be competing to be absorbed.

Any thoughts?
 

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Sorry to side track this a slight bit.

I am about to make my Rex Grigg Reactor for CO2 but then I thought about also adding a possible connection for an air pump to add o2 to the water. My thought was to have the CO2 while the plants are active (light time) and then have the air pump kick in during the non active time (dark time) to build up the oxygen in the water. I thought about also adding it during the day time but was fearful that it would inhibit the absorption of the CO2 in the water since both gasses would be competing to be absorbed.

Any thoughts?
Not at all appropriate if you have a heavily planted tank and one resists the temptation to overstock with fauna.
 

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Sorry to side track this a slight bit.

I am about to make my Rex Grigg Reactor for CO2 but then I thought about also adding a possible connection for an air pump to add o2 to the water. My thought was to have the CO2 while the plants are active (light time) and then have the air pump kick in during the non active time (dark time) to build up the oxygen in the water. I thought about also adding it during the day time but was fearful that it would inhibit the absorption of the CO2 in the water since both gasses would be competing to be absorbed.

Any thoughts?
Read the other posts in the thread. O2 and CO2 are absorbed independent of one another, they are not competing for room in between water molecules!

All the air won't go into the water, your reactor will be full of nitrogen by the end of the night. If you want to use the air pump have an airstone in the tank itself to create a good ripple on the water's surface. Better yet, have more oxygen during the day as well by increasing the ripple on the water surface by raising the filter's return and keep extra equipment out of the tank in the first place.
 
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