Oxygenation - With Skimmer Off?

[Reaf]

Where you have to turn the skimmer off to dose the tank, will surface agitation from powerheads suffice for oxygenation?

The product I am using is waste away, and would be turning skimmer off for 24hrs.

Thanks

 

[Dom]

Tell us what's going on with your tank.

Also, can you post pictures of the packaging?

 

[Subsea]

I have not used a skimmer in > 30 years. Depending on the BOD (biological oxygen demand) of your system determines oxygen consumption. If you are going to increase the oxygen demand of your system by adding “waste away”, then you should increase gas exchange. Either increase surface movement or add an air stone.

 

[Reaf]

Tell us what's going on with your tank.

Also, can you post pictures of the packaging?

Planning on using for maintenance.

 

[Reaf]

I have not used a skimmer in > 30 years. Depending on the BOD (biological oxygen demand) of your system determines oxygen consumption. If you are going to increase the oxygen demand of your system by adding “waste away”, then you should increase gas exchange. Either increase surface movement or add an air stone.

How much surface movement is required?

 

[Subsea]

How much surface movement is required?

What’s your bioload?

You need to better describe your system to get good advice.

PS: Excess circulation at surface hurts nothing unless waves are splashing out of tank.

 

[Mr. Mojo Rising]

if you are truly concerned about lack of oxygen, then just do water changes and clean your machines manually, instead of relying on bottled stuff to clean your tank which has several warnings on the label.

 

[blaxsun]

The short answer is yes. I routinely turn my skimmer off for about 48 hours once or twice a month to use FritzZyme Monster 460.

 

[Randy Holmes-Farley Verified Community Expert]

How much surface movement is required?

That's a really complicated question without a perfect answer.

I'd argue that O2 at night may be low in many tanks, even with a skimmer, but during the day O2 is much higher and that would be the time to turn off a skimmer, if you really needed to.

 

[Randy Holmes-Farley Verified Community Expert]

if you are truly concerned about lack of oxygen, then just do water changes and clean your machines manually, instead of relying on bottled stuff to clean your tank which has several warnings on the label.

How does a normal water change substantially increase O2 levels?

IMO, O2 is a reasonable concern for all reefers.

So many folks assume gas exchange is complete without any chemical evidence, and yet the diurnal pH cycle proves otherwise in nearly every reef aquarium.

I understand that CO2 is harder to equilibrate than O2, but one cannot just look at a reef tank and know there is complete gas exchange.

 

[WVNed]

Take the cup off the skimmer and let it run. Then you get the bubbles but it wont remove anything.

 

[Harold999]

Where you have to turn the skimmer off to dose the tank, will surface agitation from powerheads suffice for oxygenation?

Surface agitation is where the gas exchange happens. The amount of gas exchange around an air bubble (in skimmers or airstones) is wáy overrated because of the surface tension surrounding the bubble.

An airstone in a bucket of water helps with gasexchange simply because the bubbles agitate the surface.

 

[Randy Holmes-Farley Verified Community Expert]

Surface agitation is where the gas exchange happens. The amount of gas exchange around an air bubble (in skimmers or airstones) is wáy overrated because of the surface tension surrounding the bubble.

An airstone in a bucket of water helps with gasexchange simply because the bubbles agitate the surface.

I’m not sure I agree with that characterization.

Why do you think surface tension impacts gas exchange, and why is it different on a bubble than the tank surface?

Certainly, organics accumulated at an air/water interface can slow gas exchange, but again the question is why one would assume a difference between a bubble interface and the tank surface interface.

IMO, the important factor for gas exchange is the surface area of air/water interface, how effectively that surface is kept clean of organics, and how fast both the near-surface gas and water are exchanged with the bulk water and air.

 

[WVNed]

Surface agitation is where the gas exchange happens. The amount of gas exchange around an air bubble (in skimmers or airstones) is wáy overrated because of the surface tension surrounding the bubble.

An airstone in a bucket of water helps with gasexchange simply because the bubbles agitate the surface.

I am curious as to why you think the air-water interface in a bubble is different than the one at the surface.
I am pretty sure they are identical. It's the same salt water.
Bubbles just give you additional surface area for the air exchange to occur.

Meh Randy beat me.

 

[Malcontent]

 

[Mr. Mojo Rising]

How does a normal water change substantially increase O2 levels?

IMO, O2 is a reasonable concern for all reefers.

So many folks assume gas exchange is complete without any chemical evidence, and yet the diurnal pH cycle proves otherwise in nearly every reef aquarium.

I understand that CO2 is harder to equilibrate than O2, but one cannot just look at a reef tank and know there is complete gas exchange.

Sorry to cause confusion, I was referring to water changes as opposed to using "gunk remover" (not as a means of oxygenation).

 

[Randy Holmes-Farley Verified Community Expert]

Sorry to cause confusion, I was referring to water changes as opposed to using "gunk remover" (not as a means of oxygenation).

Got it, thx.

 

[Malcontent]

~95% of total oxygen transfer in a bubble plume is from the bubbles.

 

[Subsea]

@Randy Holmes-Farley

why don’t more people measure oxygen in their reef tanks. Is an oxygen meter at $200 an important tool?

 

[Randy Holmes-Farley Verified Community Expert]

@Randy Holmes-Farley

why don’t more people measure oxygen in their reef tanks. Is an oxygen meter at $200 an important tool?

I expect cost, no push by hobby supply companies, and general lack of discussion is the reason.

You’ve likely read them, but I think it would be helpful for more reefers to read Eric Bornemann’s series of three articles on O2, including a bunch of measurements he took.

Here’s the third one:

http://reefkeeping.com/issues/2005-08/eb/index.php