Oxygen Levels In A Planted Tank

[amagphoto]

55 gallon, freshwater, heavily planted, 2 months old, eco gravel, eheim 2217 with j hook for little surface agitation, pressurized CO2,

no2 0
no3 0
kh 7
ph in morning is 7.6
ph by night is 6.8
ei fert 3x / week
ammonia 0
hard 120 ppm

I just had 2 new rose line barbs die in 3 days....trying to figure out the cause and think it might be low oxygen levels in the daytime. Is there any way to measure the oxygen level in the tank at a given time??? My plants are doing well, and do pearl but not until about 3 hours into the morning and not going crazy pearling. Can see oxygen bubbles under my Java Ferns, and amazon swords to release bubbles, and other plants but not nearly like an air pump would. I just don't know if it's enough oxygen in the water....have 6 neons, 6 pencil fish, 3 ottos, 2 flying foxes, 7 shrimp, 2 cherry barbs, 1 rainbow. and 3 marble hatchets, all doing pretty ok. Monitoring Co2 levels every day but not sure about the oxygen, and I'm thinking that's what led to my new rose lines dying so quickly. I even run a small airstone at night but need a way to measure oxygen levels in the daytime. I know I can "add" more oxygen by attaching my eheim spray bar, but I thought with a planted tank little water agitation was more beneficial for the plants. How do you get that "balance" right??? Help.....still reeling from losing my roselines.....

signed oxygen depleted.

 

[voo]

Do you use a solenoid to turn off your CO2 during the night? That will help with the oxygen during the night, when the plants will also be using up the oxygen.
As for during the day, if there was not enough oxygen in the water for your fish then you would see them gasping at the surface for air. This is a clear sign there's not enough oxygen. If they're not gasping, then I guess the oxygen levels are fine for them.

 

[sophos9]

Bishies hate unstable PH, adding air overnight will cause your CO2 to disperse thus increasing PH. First thing, do you run CO2 over night?

My first bit of advise would be to get your PH stable so closing at night would be 6.8, first thing before lights on, 6.8!
You do not need to measure oxygen, I went through this and realised I was adding TOO much CO2 (with your KH a possible problem, how do you measure you PH?). If your plants are pearling then O2 should not be a problem, if you see all your fish kissing the surface then you have an O2 problem.

HTH

 

[JamesC]

pH fluctuations are, contrary to popular belief, no problem for fish and other livestock. Indeed in the wild there are large fluctuations during the day. Changing KH, which also changes pH, is very bad though.

With high CO2 levels you need to also have high O2 levels.
To generalise:
High CO2, high O2 - Good
High CO2, low O2 - Bad
Low CO2, low O2 - OK
Low CO2, High O2 - Good

James

 

[lljdma06]

What's the temperature?

llj

 

[amagphoto]

Do you use a solenoid to turn off your CO2 during the night? That will help with the oxygen during the night, when the plants will also be using up the oxygen.
As for during the day, if there was not enough oxygen in the water for your fish then you would see them gasping at the surface for air. This is a clear sign there's not enough oxygen. If they're not gasping, then I guess the oxygen levels are fine for them.

Thanks for the reply, yes I do use a selinoid to shut off my Co2 at night....and run a small airstone duing night. My rose lined barbs weren't gasping at the surface, but could definitely tell they were "stressed" ......breathing very fast....and none of my other fish were having any issues. I'm getting different answers even on this forum, about whether to run air at night or not, and whether PH swings are bad for fish. I'm afraid if I don't run air at night they will definitely be sucking for air by the morning.

 

[amagphoto]

Bishies hate unstable PH, adding air overnight will cause your CO2 to disperse thus increasing PH. First thing, do you run CO2 over night?

My first bit of advise would be to get your PH stable so closing at night would be 6.8, first thing before lights on, 6.8!
You do not need to measure oxygen, I went through this and realised I was adding TOO much CO2 (with your KH a possible problem, how do you measure you PH?). If your plants are pearling then O2 should not be a problem, if you see all your fish kissing the surface then you have an O2 problem.

HTH

Thank you for replying...I did read your about all your algea woes so definitely would like to hear your ideas on this problem. I do run an airstone at night for the fishies, and turn it off during the day. Plants are pearling but my Co2 I think takes a good 3 hours to get close to the 30ppm.....I think I need to keep it more stable but how do you do this? If I run air at night the Ph goes up to about 7.6 in the morning, then through the day when Co2 in running the Ph comes down to about 6.8, and my Co2 color drop indicator is in the green by night (suppose to show 30ppm when green). I've read some articles that fish do best in 15ppm and 30 ppm is too high for them (especially more sensative species???). I measure PH by regent testing and strip tests every day and measure KH also. Kh around 6-7 on average, I have pretty hard tap water and thinking about softening somehow when do water changes. How do you maintain a stable 30ppm co2 level night and day in your tank?? Help, I'm drowning in co2.

Bishies hate unstable PH, adding air overnight will cause your CO2 to disperse thus increasing PH. First thing, do you run CO2 over night?

My first bit of advise would be to get your PH stable so closing at night would be 6.8, first thing before lights on, 6.8!
You do not need to measure oxygen, I went through this and realised I was adding TOO much CO2 (with your KH a possible problem, how do you measure you PH?). If your plants are pearling then O2 should not be a problem, if you see all your fish kissing the surface then you have an O2 problem.

HTH

Thank you for replying...I did read your about all your algea woes so definitely would like to hear your ideas on this problem. I do run an airstone at night for the fishies, and turn it off during the day. Plants are pearling but my Co2 I think takes a good 3 hours to get close to the 30ppm.....I think I need to keep it more stable but how do you do this? If I run air at night the Ph goes up to about 7.6 in the morning, then through the day when Co2 in running the Ph comes down to about 6.8, and my Co2 color drop indicator is in the green by night (suppose to show 30ppm when green). I've read some articles that fish do best in 15ppm and 30 ppm is too high for them (especially more sensative species???). I measure PH by regent testing and strip tests every day and measure KH also. Kh around 6-7 on average, I have pretty hard tap water and thinking about softening somehow when do water changes. How do you maintain a stable 30ppm co2 level night and day in your tank?? Help, I'm drowning in co2.

Forgot to answer, no I do not run Co2 at night....selonoid shuts it off....use the RedSea Pro Co2 system....

What's the temperature?

llj

Temp is 78 degrees.

 

[voo]

I just had 2 new rose line barbs die in 3 days....

What makes you think it's because of a lack of oxygen? If they were new fish, it could just have been the stress of being moved. Also, if your CO2 is off during the night, i dont see any need to be using an airstone.

 

[SuperColey1]

The airstone overnight usually applies only to people who are running CO2 24 hours to drive it off at night (often worried DIYers)

If there is no CO2 being pumped in overnight then there is no need to do this as the CO2 will naturally disperse over a time once the solenoid kicks in (should be 2 hours before lights out) and then you can get the CO2 to build up again 2 hors before lights on

It has been suggested many times that if theres too much CO2 there will be less O2 which is false as they are 2 seperate entities. Its just that the fish breathe O and release CO2 and the plants take in CO2 when they are photosynthesising and O when they are not.

If the temp is too high then O will become less but 78 is not so high. How are you measuring temp or is this just what you set the heater to?

Therefore if the temp is 78, The fish are not all kissing the surface and you are already using a solenoid AND airstone at night, it can only be the water parameters, or disease or something else but not O/CO2.

Keep an eye on the CO2 though and buy a drop checker, then you would know within a couple of hoursw if there was too much CO2 in there.

Andy

 

[amagphoto]

The airstone overnight usually applies only to people who are running CO2 24 hours to drive it off at night (often worried DIYers)

If there is no CO2 being pumped in overnight then there is no need to do this as the CO2 will naturally disperse over a time once the solenoid kicks in (should be 2 hours before lights out) and then you can get the CO2 to build up again 2 hors before lights on

It has been suggested many times that if theres too much CO2 there will be less O2 which is false as they are 2 seperate entities. Its just that the fish breathe O and release CO2 and the plants take in CO2 when they are photosynthesising and O when they are not.

If the temp is too high then O will become less but 78 is not so high. How are you measuring temp or is this just what you set the heater to?

Therefore if the temp is 78, The fish are not all kissing the surface and you are already using a solenoid AND airstone at night, it can only be the water parameters, or disease or something else but not O/CO2.

Keep an eye on the CO2 though and buy a drop checker, then you would know within a couple of hoursw if there was too much CO2 in there.

Andy

Andy,

I really appreciate your advice.....this is my first planted tank and is doing well for my plants...this Co2 and oxygen balance is tricky business. Will the drop checker be more accurate than my Red Sea Carbon dioxide monitor (which actually measures the Ph to give you the color for good Co2). Should I lower the temp to 76 degrees to help with the oxygen exchange/levels. Right now I use a solenoid when lights out, not 2 hours before lights out, and then turn on small airstone through the night. Water paramaeters test good consistently, just a swing in the Ph of .8 to 1 full point from morning to night.

 

[Maximumbob]

I'm not sure what benefit an airstone would have regarding oxygenation of the tank overnight. You already have the j hook set up for surface agitation.

As Oxygen doesn't dissolve in water very easily and most of the gaseous exchange happens at the surface of the water. By agitating it you increase the surface area and improve gaseous exchange. An airstone works by aggitation the surface area also.

I suspect what you will do by having an airstone on at night is drive off more CO2 and add little to oxygen exchange. IMHO this would provide a fluctuating pH with only marginal (if any) improvement in Oxygen levels. The correct thing to do is agitate the surface with your filter outlet - which you are doing. I don't think an airstone would benefit unless your fish are showing obvious signs of too much CO2. I think your fish would appreciate the steady tank parameters. If you are still worried another thing which I think would help is reducing tank temp to about 75-6 degrees. Cooler water has an increased carrying capacity for oxygen.

As for a cause of death - i'm not sure we will ever figure it out unless something else declares itself. At a best guess I would just say it was because the tank is just 2 months old, occasionally thing like this happen in new tanks. But, as always with deaths - close monitoring and testing for the next week or so.

Another thing to bear in mind is that sometimes the water which we put in the tank changes - a recheck of your tap water may provide some clues. I once heard of a man who lost all his fish because there was a rise in the levels of copper in his tap water. It was within limits for humans - just not fish

 

[amagphoto]

I'm not sure what benefit an airstone would have regarding oxygenation of the tank overnight. You already have the j hook set up for surface agitation.

As Oxygen doesn't dissolve in water very easily and most of the gaseous exchange happens at the surface of the water. By agitating it you increase the surface area and improve gaseous exchange. An airstone works by aggitation the surface area also.

I suspect what you will do by having an airstone on at night is drive off more CO2 and add little to oxygen exchange. IMHO this would provide a fluctuating pH with only marginal (if any) improvement in Oxygen levels. The correct thing to do is agitate the surface with your filter outlet - which you are doing. I don't think an airstone would benefit unless your fish are showing obvious signs of too much CO2. I think your fish would appreciate the steady tank parameters. If you are still worried another thing which I think would help is reducing tank temp to about 75-6 degrees. Cooler water has an increased carrying capacity for oxygen.

As for a cause of death - i'm not sure we will ever figure it out unless something else declares itself. At a best guess I would just say it was because the tank is just 2 months old, occasionally thing like this happen in new tanks. But, as always with deaths - close monitoring and testing for the next week or so.

Another thing to bear in mind is that sometimes the water which we put in the tank changes - a recheck of your tap water may provide some clues. I once heard of a man who lost all his fish because there was a rise in the levels of copper in his tap water. It was within limits for humans - just not fish

Appreciate the advice, and I will go ahead and take out the airstone at night and see if the Ph stays a little more stable. Question, if my plants are beading some, not a ton, is that a sign the water is being oxygenated enough? The beads sit under the leaves of my java ferns, also are released from swords and other plants once the co2 levels are built up to around 30ppm. I read an article stating co2 levels with fish should be kept around 15ppm, but when I read about plant CO2 levels should be around 30ppm. This begs another questiion.....how do you maintain a stable level of 30ppm (recommended for plants) if your co2 is turned off at night? I'll try the no airstone thing and lower the temp to 76 degrees slowly. Thanks again.

I'm not sure what benefit an airstone would have regarding oxygenation of the tank overnight. You already have the j hook set up for surface agitation.

As Oxygen doesn't dissolve in water very easily and most of the gaseous exchange happens at the surface of the water. By agitating it you increase the surface area and improve gaseous exchange. An airstone works by aggitation the surface area also.

I suspect what you will do by having an airstone on at night is drive off more CO2 and add little to oxygen exchange. IMHO this would provide a fluctuating pH with only marginal (if any) improvement in Oxygen levels. The correct thing to do is agitate the surface with your filter outlet - which you are doing. I don't think an airstone would benefit unless your fish are showing obvious signs of too much CO2. I think your fish would appreciate the steady tank parameters. If you are still worried another thing which I think would help is reducing tank temp to about 75-6 degrees. Cooler water has an increased carrying capacity for oxygen.

As for a cause of death - i'm not sure we will ever figure it out unless something else declares itself. At a best guess I would just say it was because the tank is just 2 months old, occasionally thing like this happen in new tanks. But, as always with deaths - close monitoring and testing for the next week or so.

Another thing to bear in mind is that sometimes the water which we put in the tank changes - a recheck of your tap water may provide some clues. I once heard of a man who lost all his fish because there was a rise in the levels of copper in his tap water. It was within limits for humans - just not fish

Appreciate the advice, and I will go ahead and take out the airstone at night and see if the Ph stays a little more stable. Question, if my plants are beading some, not a ton, is that a sign the water is being oxygenated enough? The beads sit under the leaves of my java ferns, also are released from swords and other plants once the co2 levels are built up to around 30ppm. I read an article stating co2 levels with fish should be kept around 15ppm, but when I read about plant CO2 levels should be around 30ppm. This begs another questiion.....how do you maintain a stable level of 30ppm (recommended for plants) if your co2 is turned off at night? I'll try the no airstone thing and lower the temp to 76 degrees slowly. Thanks again.

One last note, the eheim j hook actually decreases surface agitation, again thought this was better for plants, it is pointed directly in the corner of my tank over the co2 reactor. I could change to the spray bar but thought this was too much surface agitation for planted tanks. Some folks on this forum have their spray bars pointed down towards the bottom for just this reason. Which is better???

 

[Maximumbob]

personally i orientate my spray bar at 90 degrees and have it 5-10 mm below the surface. Causes riplles - but not a lot.

As regarding your CO2 levels. If you switch it off at lights out. The plants stop using it until lights on again - so it remains steady.

 

[amagphoto]

personally i orientate my spray bar at 90 degrees and have it 5-10 mm below the surface. Causes riplles - but not a lot.

As regarding your CO2 levels. If you switch it off at lights out. The plants stop using it until lights on again - so it remains steady.

Do you think I should go back to the spray bar? I have the j hook pointed at the corner of the tank over my co2 reactor...so not as much water agitation as with the spray bar. I'm leaving oxygen off tonight and will check ph levels in morning. Appreciate the advice.

 

[Maximumbob]

Do you think I should go back to the spray bar? I have the j hook pointed at the corner of the tank over my co2 reactor...so not as much water agitation as with the spray bar. I'm leaving oxygen off tonight and will check ph levels in morning. Appreciate the advice.

I would just experiment and see. Expect to increase the amount of CO2 you are using when you increase the surface aggitation. Although your usage increases, concentrate on tank levels of CO2 - thats what matters.