The rationale behind running a airstone at night

[|squee|]

I've noticed that some people run and airpump into their tank at lights-off. Some say it's good, some say it's not necessary.

What exactly is the rationale behind it? Takashi Amano also aerates his tanks after lights-off, the reason stated by him to be " to aid oxidation for plants ". Does anyone understand this?

I hesitate to experiment, because I'm worried that the pH fluctuation at night might be too rapid for my fishes to bear.

Comments anyone?

[Simon]

[quote:fcbe00ae74="|squee|"]I've noticed that some people run and airpump into their tank at lights-off. Some say it's good, some say it's not necessary.

What exactly is the rationale behind it? Takashi Amano also aerates his tanks after lights-off, the reason stated by him to be " to aid oxidation for plants ". Does anyone understand this?

I hesitate to experiment, because I'm worried that the pH fluctuation at night might be too rapid for my fishes to bear.

Comments anyone? [/quote:fcbe00ae74]

pH flunctuation thru out the day is actually normal, perhaps some of them running with pH controller, so aeration helps supply o2 to the fishes?

[PeterGwee]

If a tank has plants that are in great health and growing well, you would normally have O2 concentration above saturation point (over 100%..aka high pearling rates). You would want to keep this O2 produce by plants as long as possible through the night. Aerating the tank after the O2 has drop below 100% is fine which occurs several hours after the lights went off (depends on bioload and bacteria demand.). Aerating the tank immediately after the photoperiod serve no purpose as it actually drives off the excess O2.

Some folks have issues if they don't aerate their tank in the night probably due to high fish load or too little surface turnover. A simple and better method is to have moderate surface movement and hence the need of night time aeration is not needed then. (Do note that night time aeration drives off a lot of CO2 as well...if you have an efficient CO2 system, you can return it to 25-35ppm within and hour or so but not for a wimpy setup.)

Regards
Peter Gwee

[anzai]

Instead of using an airpump, would the surface turbulance caused by a fan or a surface skimmer suffice?

[benny]

When I had pretty high bioload in my 5 ft planted set up, I used to run a air pump on timer. it comes on 1 hour after the lights goes out and turns off 1 hour before.

The fishes and plants were not affected and your don't see fishes gasping for air in the morning.

Cheers,

[|squee|]

Hmmm... seems there's no actual need to run a airpump at night.

But why the heck does Amano do it? I'm pretty interested in his way of doing things :P Anyone knows?

[anzai]

I think its because the plants are competing with the fish for oxygen at night due to the lack of photosynthesis, causing a massive depletion of oxygen in the water. Hence there is a need to aerate the water.

[Supergrass]

If a tank is heavily fish populated, aeration of an airstone during light off can easily remove off any excess CO2 and supplement the dissolved oxygen within the tank.

In a properly buffered and densely planted tank that is not overstock, mostly the oxygen level in the tank remains high enough, and the pH in the tank remains more stable, without the interference of night time aeration.

[cairocks]

[quote:083e79c02f="anzai"]Instead of using an airpump, would the surface turbulance caused by a fan or a surface skimmer suffice?[/quote:083e79c02f]
I had tried using 3 fans for last 2 days, turned on during alternate hours thru the night using timer. Seems to be working.Didn't see fish gasping for air in the morning. But need further confirmation during the weekends. Had that problem last time if there isn't any fans or air pump on during the night. Think might be caused by my fluidized bed filter which I read can use up quite a lot of oxygen.