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View Full Version : Aeration in a planted tank at night.



Hank
03-03-2011, 7:15 PM
I was reading Tropical fish Hobbyist Magazine and I went directly to Takashi Amano section to look at his aquascapes. I noticed in his data of his set-ups, he adds aeration for 14 hrs after lights are out. I would like to know for any other reason besides off gassing CO2 and creating more O2?

prober
03-03-2011, 8:04 PM
Because plants and animals both use oxygen at night and low oxygen levels are one cause of algae. During the time the lights are on the plants provide oxygen.

GraphicGr8s
03-04-2011, 8:24 AM
Adding an airstone doesn't really add more O2 to the water in and of itself. What it does is create more surface area for the water/atmosphere interface. It also decreases the surface tension at the water's surface allowing more offgassing.

rockhoe14er
03-04-2011, 8:36 AM
Because plants and animals both use oxygen at night and low oxygen levels are one cause of algae. During the time the lights are on the plants provide oxygen.

I've never heard this before. Can i ask where you got this?

I always thought the reason for an air stone at night was to cause surface agitation to help off gas the co2 and increase the O2 concentrations to atmospheric levels so that it's less stressful on the fish.

I don't need an air stone because i have high surface current 24/7 to make co2 dosing less stressful on my inverts. (this also allows you to run higher co2 ppm because you can increase o2 levels by doing this.)

Hank
03-04-2011, 11:02 AM
Can we get back to the original thread! Pleaseee! Why does Amano use aeration at night besides creating O2! Are there other reasons?

WeedCali
03-04-2011, 11:08 AM
I think thats it... To increase the O2 levels so the fish can breathe.

plantbrain
03-04-2011, 11:08 AM
Because plants and animals both use oxygen at night and low oxygen levels are one cause of algae. During the time the lights are on the plants provide oxygen.

Low O2 does NOT cause algae.

gt1009
03-04-2011, 11:16 AM
He adds the airstone to increase O2. This is because at night your plants go into a different state of respiration where instead of using CO2 for photosynthesis, they use 02 for another chemical process (glycolysis or something I can't quite remember, it's been a while since I took plant bio). If you CO2 systems run at night, the airstone allows your fish to get some oxygen instead of saturating the water completely with CO2. If you have a solenoid on your pressurized CO2 system, then it is not needed as bad as with a DIY or pressurized system without a solenoid, but still is useful in a high light setup where your CO2 levels will rise rapidly after the lights turn off and the plants stop producing O2. Hope this helped.

plantbrain
03-04-2011, 11:17 AM
I was reading Tropical fish Hobbyist Magazine and I went directly to Takashi Amano section to look at his aquascapes. I noticed in his data of his set-ups, he adds aeration for 14 hrs after lights are out. I would like to know for any other reason besides off gassing CO2 and creating more O2?

With canister filters, the CO2 stays higher than say with a wet/dry sealed filter(another thread on how to correctly set one up for a planted tank) at night time.
Some use a powerhead or a airstone at night to help add O2 for the fish, this does not help the plants however(got nothing to do/help for them one bit).
If you use a wet/dry, then you can have a high fish load and healthy system without doing this.

ADA tanks tend to have VERY sparse fish populations, and low current.
If you have higher current, then enough O2 comes in 24/7 to avoid this altogether.
Some folks do not like higher current.

I do.

Since the O2 is also higher during the day(I've used a calibrated O2 meter to measure it over the day at 15 min intervals), I have more flexibility to add more CO2 since there's les sO2 stress to the fish.
Fish also get more exercise in higher current. A good rule is to have enough surface movement to just not quite break the surface.
If you really aerate and break the surface, you will degas the CO2 too rapidly.

A sealed(eg duct tape the top edge and air vents) wet/dry chamber(not the down stream sump) will redissolve any degassed CO2, but since O2 and CO2 are independent, it still adds more O2 as the water coming down the stand pipe still enters the chamber and the added O2 dissolves, just like the CO2 does.
Aeration at night is not needed for such systems, even with 5x more fish loading than the ADA tanks.
Also allows a lot more wiggle room dosing CO2 without stressing fish as much.

Since improper CO2 gas usage is the no1# killer of fish in planted tanks.........not a bad idea to work on.

plantbrain
03-04-2011, 11:19 AM
He adds the airstone to increase O2. This is because at night your plants go into a different state of respiration where instead of using CO2 for photosynthesis, they use 02 for another chemical process (glycolysis or something I can't quite remember, it's been a while since I took plant bio). If you CO2 systems run at night, the airstone allows your fish to get some oxygen instead of saturating the water completely with CO2. If you have a solenoid on your pressurized CO2 system, then it is not needed as bad as with a DIY or pressurized system without a solenoid, but still is useful in a high light setup where your CO2 levels will rise rapidly after the lights turn off and the plants stop producing O2. Hope this helped.

This is NOT for the plants, the O2 concentration would have to be extremely low, e a 100% lethal level for virtually any fish before the plants are limited in any way in terms of respiration.
Plants just do not need much O2 in other words to carry on respiration.

GraphicGr8s
03-04-2011, 11:54 AM
How much O2 do you think an airstone can add to water? The important thing they do is increase water surface/air interchange. They break the meniscus That's about the only place you get an exchange of gases. Even injecting pure O2 (not recommended since it supports combustion) will not increase O2 levels drastically. Your O2 rates go up during the day because of the plants.

Cerianthus
03-04-2011, 12:15 PM
If O2 is injected into tank via proper reactor, yes it can/will cause drastic increases in dissolved [O2], a supersaturation, a condition not necessarily good for fish either. No need to if surface is well agitated via filter/aeration and find right balance for each individual tank.

btw, if memory serves, cellualar repiration takes place even during daytime. A topic too complicated to go in detail, not that I know/remember much.

Hank
03-04-2011, 3:51 PM
Tom Barr,
Thank you again. I will not be using aeration at night. I hope some of the members who posted on this thread learned something from you.

Cerianthus
03-04-2011, 4:19 PM
Tom Barr,
Thank you again. I will not be using aeration at night. I hope some of the members who posted on this thread learned something from you.

Nothing new actually. All depends on each individual's need as somewhat explained case by case By TB.

plantbrain
03-04-2011, 5:36 PM
Nothing new actually. All depends on each individual's need as somewhat explained case by case By TB.

Yep

bluemeate
03-05-2011, 2:49 AM
I would like to know for any other reason besides off gassing CO2 and creating more O2
ive heard fluctuating co2 promotes algae... hows it relate to that?

plantbrain
03-05-2011, 10:11 PM
ive heard fluctuating co2 promotes algae... hows it relate to that?


Would it stress you out if you had say 800 calories per day, then suddenly say 3000? Then 800, then 500, then 4000?

Same sort of thing.

Plants largest enzyme by total mass is Rubisco(the planet's for that matter), the amount is strongly regulated by CO2 concentration.
If the CO2 is moving all over and dipping into the limiting ranges for part of the day etc, then it will cause growth problems.
Algae have very little issue since their carbon demand is 10-1000X less than plants. Algae spores seem to sense this change, and plants stop growing.
Then algae attacks and grows all over the plants. So the focus is more on the growth growth of plants, then algae are rarely ever an issue and then only minor at that.
I've been saying this last part for the last 20 years.

Hank
03-06-2011, 7:06 PM
Tom Barr,
Now this brings me back to Amano ADA tanks. How about the fluctuations of the pH? During the day he injects CO2 and the pH comes down. He does this for ten hrs. Lights out, aeration on for 14 hrs. and CO2 is degassed bringing the pH back up to its normal, what ever that might be.
If this was my situation and I applied aeration at night within 24 hrs my pH would go from 6.8 to 6.2. So every 24 hrs I would have this yo-yo effect. Would this create a problem?

rockhoe14er
03-07-2011, 8:28 AM
pH fluctuations because of co2 pose little problems to fish or to promote algae. However pH differences because of TDS do harm fish (this can cause osmatic shock in fish and can cause them to either gain or lose excess water). The yo-yo effect that you refer to will have no effect on anything. My pH drops much more than that. My tap water is 7.6 and my tank after an hour of co2 on is around 6.4. I have lots of rcs and they don't mind and this doesn't seem to cause any algae in my tanks.

just focus on the plants needs and you won't have algae.

plantbrain
03-07-2011, 10:40 AM
Tom Barr,
Now this brings me back to Amano ADA tanks. How about the fluctuations of the pH? During the day he injects CO2 and the pH comes down. He does this for ten hrs. Lights out, aeration on for 14 hrs. and CO2 is degassed bringing the pH back up to its normal, what ever that might be.
If this was my situation and I applied aeration at night within 24 hrs my pH would go from 6.8 to 6.2. So every 24 hrs I would have this yo-yo effect. Would this create a problem?

Does not matter since the CO2 is good throughout the day cycle only, night does not matter.
Plants, algae etc do not use it it at night, well....a few CAM species, but they are rare and few keep them.
Most everyone does not add CO2 at night to maintain pH.
This is an old myth that pH is really important where CO2 is added.
Relatively to measure CO2, but not in and of itself.

plantbrain
03-07-2011, 10:40 AM
pH fluctuations because of co2 pose little problems to fish or to promote algae. However pH differences because of TDS do harm fish (this can cause osmatic shock in fish and can cause them to either gain or lose excess water). The yo-yo effect that you refer to will have no effect on anything. My pH drops much more than that. My tap water is 7.6 and my tank after an hour of co2 on is around 6.4. I have lots of rcs and they don't mind and this doesn't seem to cause any algae in my tanks.

just focus on the plants needs and you won't have algae.

+1

Cerianthus
03-07-2011, 10:46 AM
I personally had less fluctuation in pH/[CO2] when CO2 was appropriately injected during lighted hours. More/higher pH fluctuation without CO2 injection in Dutch Aq.

I kept pH/[CO2] pretty much constant day and night (CO2 inject during most lighted hours of course) with sporatic aeration (duration and frequency as needed per specific tank) as per tank during night in a tanks that were heavily stocked .

Perhaps one may be injecting too much and wasting CO2 if there were that much flutuations in pH/[CO2].
And most importantly, such condition maybe not yield the optimal conditions for all inhabitants.

Finding right balance is the key and this balance maybe different as per tank.

One should find right balance for his/her own individual tank for optimal results, that is including fish.

Hank
03-07-2011, 11:29 AM
I thank you all for the helpful posts about fluctuation of pH. Lets not forget aeration at night...Thanks

Cerianthus
03-07-2011, 2:25 PM
Actually waiting for Mr. PlantBrain's reply in hopes of learning something new! Hopefully he responds!

Hank
03-07-2011, 4:38 PM
I personally had less fluctuation in pH/[CO2] when CO2 was appropriately injected during lighted hours. More/higher pH fluctuation without CO2 injection in Dutch Aq.

I kept pH/[CO2] pretty much constant day and night (CO2 inject during most lighted hours of course) with sporatic aeration (duration and frequency as needed per specific tank) as per tank during night in a tanks that were heavily stocked .

Perhaps one may be injecting too much and wasting CO2 if there were that much flutuations in pH/[CO2].
And most importantly, such condition maybe not yield the optimal conditions for all inhabitants.

Finding right balance is the key and this balance maybe different as per tank.

One should find right balance for his/her own individual tank for optimal results, that is including fish.

I wasn't going to dignify this post but I know this will annoy you, maybe just a little...
My question was very simple. Would fluctuation of pH cause a problem. The first two paragraphs are about you. The third paragraph only means that you didn't understand my post. I don't have pH fluctuation!
Now you want to discuss a balance aquarium, how about another time?
I don't know what you have against Tom Barr but I know who he is! Just Google him.

Hank
03-07-2011, 4:42 PM
Actually waiting for Mr. PlantBrain's reply in hopes of learning something new! Hopefully he responds!

He will not give you the pleasure......

Cerianthus
03-07-2011, 8:04 PM
He will not give you the pleasure......

Hakuna matata!:)

Fortuantely or should I say unfortunately, I dont get annoyed, especially over fish thats out of my reach, not that I want to when keepers dont want me to:). .

I dont know where you got the notion that I dislike anyone in the forum? If I dont agree/share same thoughts, it automatically = dislike??

Whether he does or not, it's not the end of the world as all I wanted was opinions/tips from such reputable person in the industry but not a must.:)

Comprehend what i wrote, all are related to to your topic. Perhaps you dont agree but as with any others forums, hoping someone, even one, may/will comprehend & utilize what I given or take it into consideration in one's tank.:)

plantbrain
03-07-2011, 11:20 PM
Play nice kids. It's off topic not to.

Many assume that pH change is detrimental, which may be true in systems lacking algae/plants.......
But in natural systems, pH can change 2 full units in marine systems(can you think of some??) and up to 4 full units, 6 up to a pH of 10 in freshwater, but 2 units is typically more common, and both spots have nice lush plants and fish populations.

If you do a large water change, a full unit of change will occur in say 5 minutes or less depending how fast you refill the tank.
Fish are always happy, week after week, year after year, breed etc. I do not use aeration at night, one more thing to add and noise/spray of the water causing lime deposits etc.
Does not hurt otherwise.

Seems simpler to just increase current at the surface and then you have good O2 24/7 instead of just at night.
CO2 can be adjusted with a good valve regardless of the small difference degassing rate, eg:
Ideal valve 1/8th vernier micrometer handle
V 52-4-12

A tad $$ but well worth it.
Excellent(the best) USA made precision made valve. The micrometer handle makes adjustments VERY easy.
Why? Because you can adjust it per tick mark slow and progressively and watch the fish/plants/algae for responses to CO2.

The dose is changed with the valve.
This way it is relative to the fish, the plants and the algae, not pH, not KH or other methods.
After you slowly dial this CO2 "rate" in for optimal results...........then you can go back and use a method to measure what this rate is and the pH etc.
This is a simple method and requires some patience, and slow stready adjustments.
You estimate the rate at a gross level, then dail it in precisely and tweak from there, being careful to observe fish, never change the CO2 dosing rapidly, or adjust i much and then leave for the rest of the day. Do this when you are going to be around to watch the tank closely.

A good valve, good check valve, good regulator etc, and a good diffusion method will go a long way, but.........so will some decent surface current, and will make dosing CO2 MUCH EASIER without gassing your fish.
Gassing the fish involves CO2 and O2 ratio, not one, but both gases need to be considered, not just CO2 etc. Spend your time focusing on CO2, using less , not mor elight intensity, this will help everyone a lot more than personal squabbles.

Cerianthus
03-08-2011, 8:50 PM
Thx for your time! Although you may have partially responded, I was anticipating more detailed and professional evaluation of my thoughts/practices as I was waiting for even harsh criticisms, if any (best way to learn and most importantly, to REMEMBER according to some of my mentors). Perhaps some other time in some other forum!;)

btw, "pH can change 2 full units in marine systems(can you think of some??)"
A homework?? Too old for a HW :p:

Although have some idea, maybe in diff time table/cycle but cant make a firm grip! Perhaps you can shed some light if and when possible.

Thx in adv.:)

plantbrain
03-08-2011, 11:11 PM
Hint for the marine part:
Where might there be easy to observe marine life, high plant/macro algae density, fish, inverts etc is a temporarily closed system 2X a day?
pH goes from about 8 to 10 or a tad over that sometimes.

Shallow FW ponds with thick weed growth, low alkalinity will easily move 2 or more units of pH.

Cerianthus
03-08-2011, 11:51 PM
Hint for the marine part:
Where might there be easy to observe marine life, high plant/macro algae density, fish, inverts etc is a temporarily closed system 2X a day? :rolleyes:Haha, Easy enough.:hitting:

pH goes from about 8 to 10 or a tad over that sometimes. Well, at/on most intensive areas but not all. Must check it out during night fishing.
Hopefully I dont have to jump into water at night,even shallow. :nono: :grinyes:

Shallow FW ponds with thick weed growth, low alkalinity will easily move 2 or more units of pH. That much I knew but so many variables influencing outcome as in nature. No two lakes are alike, etc.:)

bluemeate
03-09-2011, 4:52 AM
look at it this way... if in nature somehow water areas usually end up getting more/replenished oxygen during the night then plants have probably adapted to make the most of that situation and would likewise benifit from similar setting within the tank.... what yall think about that thought?