Skimmers

[Bob I]

Originally Posted by KrazyKuch

to this new system.....I believe it's not neccessary to have a skimmer on any tank but after having one and seeing what it pulls out of the water I would never go without one on any tank!!!

In a sense we are hijacking this thread, but what the H, it increases my post count.

I think you have hit on what a skimmer actually does. Skimmers basically interrupt natural decomposition of proteinaceous materials by removing large protein molecules before the natural dissolution of those molecules into nitrogenous compounds occur. That is all they do. Natural laws of physics state that they cannot increase the oxygen content of the water. (sorry Sam, still can't buy your argument}. They do not remove Phospates, or other contaminants.

That is all I will say on this matter. If anyone can prove that any of this is not true, I would welcome the input, but please make it proof NOT just opinion.

[StirCrazy]

Originally Posted by Bob I

I think you have hit on what a skimmer actually does. Skimmers basically interrupt natural decomposition of proteinaceous materials by removing large protein molecules before the natural dissolution of those molecules into nitrogenous compounds occur.

ok so by doing this is it not also removing the organic phosphates bound in that organic mater and preventing it from being released as inorganic phosphate during the decay process?

so basically a skimmer is removing phosphates.

Originally Posted by Bob I

That is all they do. Natural laws of physics state that they cannot increase the oxygen content of the water. (sorry Sam, still can't buy your argument}.

actually a bubbler in a tank will raise the O2 content also as every little bubble made is now a water/air surface interface. while not as efficient as having a turbulent water surface it still increases O2 levels, a skimmer is just basically a bubbler on steroids and does a very good job of increasing O2

Originally Posted by Bob I

They do not remove Phospates, or other contaminants.

See your first statement, do you not consider decaying organic matter contaminants? but yes aside from Phosphates they do remove several other things.

Originally Posted by Bob I

That is all I will say on this matter. If anyone can prove that any of this is not true, I would welcome the input, but please make it proof NOT just opinion.

Ok there was a test done on various skimmers and they effectiveness of removing phosphates, metals, ect from the tank water. I will find it for you to read. no time right now as I have to get out of here and Finnish my Christmas shopping

Steve

[Bob I]

Originally Posted by StirCrazy

actually a bubbler in a tank will raise the O2 content also as every little bubble made is now a water/air surface interface. while not as efficient as having a turbulent water surface it still increases O2 levels, a skimmer is just basically a bubbler on steroids and does a very good job of increasing O2

Steve

I am afraid that may sound good, but there is a problem with it. If there was an air/water interface all the bubbles would disappear before reaching the surface. There is a serious flaw in that argument.

And now that I see that there is agitation within the skimmer so theoretically oxygen gets taken up, I am bothered by another thing. How about the oxygen depletion caused by beating the crap out of the water with an impeller causing the bubbles in the first place
I just cannot see how there would be in increase in oxygen content.

[christyf5]

Originally Posted by Bob I

I am afraid that may sound good, but there is a problem with it. If there was an air/water interface all the bubbles would disappear before reaching the surface. There is a serious flaw in that argument.

And now that I see that there is agitation within the skimmer so theoretically oxygen gets taken up, I am bothered by another thing. How about the oxygen depletion caused by beating the crap out of the water with an impeller causing the bubbles in the first place
I just cannot see how there would be in increase in oxygen content.

How does an impeller deplete oxygen? Is it organic and has a requirement for oxygen?? Sheesh Bob, where do you come up with your ideas?

Actually a skimmer serves to oxygenate the water by producing fine bubbles that take longer to reach the surface thereby increasing the contact time with water and increasing the oxygen content of the water vs. larger bubbles which jet to the surface much faster and have a more limited contact time.

Christy

[Bob I]

Originally Posted by christyf5

How does an impeller deplete oxygen? Is it organic and has a requirement for oxygen?? Sheesh Bob, where do you come up with your ideas?

If you don't understand what I am getting at, I will not try explain further. I have hijacked this thread enough.

Actually a skimmer serves to oxygenate the water by producing fine bubbles that take longer to reach the surface thereby increasing the contact time with water and increasing the oxygen content of the water vs. larger bubbles which jet to the surface much faster and have a more limited contact time.

Christy

Again you don't understand the premise. I cannot explain it better, but no it will not happen. Simple concept known as surface tension keeps it from happening.

[StirCrazy]

Originally Posted by Bob I

.
Again you don't understand the premise. I cannot explain it better, but no it will not happen. Simple concept known as surface tension keeps it from happening.

Ok Bob, got you some info on it from a pond page.

"Mechanical aerators agitate water to produce liquid/air contact, while underwater diffusers introduce bubbles from a depth to achieve oxygen transfer and mixing. Bubble type aeration systems are replacing many mechanical aerators because of their low maintenance, reliability, safety, flexibility and overall efficiency. They excel where small amounts of aeration are needed in many locations. Bubble aerators are also better at removing gases, such as ammonia and carbon dioxide. Diffusers are made to deliver either coarse (approximately 6 mm), medium (approximately 3 mm), or fine (approximately 1 mm) air bubbles. Coarse-bubble systems require the lowest air pressure and are very resistant to clogging, but are about a third as efficient as medium-bubble systems in transferring oxygen to the water. The medium-bubble diffuser requires only slightly higher air pressure, but its superior oxygen transfer more than compensates for the increase in maintenance due to occasional clogging. The fine-bubble diffuser’s superior oxygen transfer usually does not compensate for its higher-pressure requirement and much more frequent clogging."



SO as you can see a bubbler type set up is the most efficient at raising O2 levels and driving off other gasses, and the smaller the bubble the higher the efficiency.

here is a chart on the different amounts of O2 that can be put into the water by different aerators. air compressor liner type is you basic bubble stone on a fish tank, and the water pump with venturi is your basic skimmer.

Aerator
Flow rate
Watts used
Grams O2 per hour
Cost per 100 grams
Lazy Stream 12" drop
10gpm
150watts
1.2
$1.26
Babbling Stream 12" drop
10 gpm
150
2.4
.63
Waterfall 12" drop straigh into pond
10gpm
150
1.4
1.05
Waterfall 2-24" drop fallng on rocks
10 gpm
200
3.1
.65
Fountain
5 gpm
100
1.6
.63
water pump with venturi
4 gpm
100
4.0
.25
Air compressor linear type 1
1 cfm
30
4
$0.06



Don't know what else to say to you on the Bob aside from please read up on it if you are having a hard time understanding it as what you are thinking isn't true.

Steve

[Samw]

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

"Figure 1 shows the oxygen dynamics of Tank 1 in operation without a skimmer. Figure 2 shows the oxygen dynamics of Tank 2 with a skimmer in operation."

"I had assumed (wrongfully) that oxygen was maintained at high levels through the use of two powerheads that agitated the water's surface. However, once the lights went out and photosynthesis stopped, oxygen levels dropped quickly from a high of 78.7% of saturation to a hypoxic low of 16% of saturation. "

Notice the skimmer took the tank from 16% to about 80+% with only the addition of a skimmer and all else constant in Tank 1. In Tank 3, the tank wasn't oxygen starved at any time so it was more difficult to see the effect of the skimmer since his tank was never low in DO even at night. It would have been useful to see the effect of a skimmer on a large tank that has a low DO level at night.

I think some people have low DO levels at night and never know it. It seems that clownfish can survive at 16% for some time whereas I'm quite sure angels can't. This explains why I've lost angels the morning after I forgot to turn my venturi back on in a skimmerless tank.

[Bob I]

Originally Posted by Samw

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

"Figure 1 shows the oxygen dynamics of Tank 1 in operation without a skimmer. Figure 2 shows the oxygen dynamics of Tank 2 with a skimmer in operation."

"I had assumed (wrongfully) that oxygen was maintained at high levels through the use of two powerheads that agitated the water's surface. However, once the lights went out and photosynthesis stopped, oxygen levels dropped quickly from a high of 78.7% of saturation to a hypoxic low of 16% of saturation. "

Notice the skimmer took the tank from 16% to about 80+% with only the addition of a skimmer and all else constant in Tank 1. In Tank 3, the tank wasn't oxygen starved at any time so it was more difficult to see the effect of the skimmer since his tank was never low in DO even at night. It would have been useful to see the effect of a skimmer on a large tank that has a low DO level at night.

I think some people have low DO levels at night and never know it. It seems that clownfish can survive at 16% for some time whereas I'm quite sure angels can't. This explains why I've lost angels the morning after I forgot to turn my venturi back on in a skimmerless tank.

There you go, you have the figures, but unfortunately natural laws in the world do not support them. Gas exchange at the water surface occurs due to surface agitation period That is how it happens in the oceans, which do not have skimmers BTW.
As far as Angels go, I have a Heraldi now, and have had many in the past. I have a small tank without a skimmer, and have never had an angel gasping for air. Let alone lose one.
Unfortunately this argument will never end because you have your beliefs, and I mine. As long as I am successful I will never change.

[Samw]

Come on Bob. No one is arguing that oxygenation doesn't occur at the surface. That's what the skimmer does. If you are going to say that the skimmer doesn't add oxygen to your tank, at least have a way to back it up by having some measurements before and after. If you can measure your tank before a skimmer is added and after a skimmer is added and show that it doesn't raise a tank's DO from a low level to a high level, then you'll have a point.

If you think that I am saying oxygenation does not occur at the surface, then you are arguing for the sake of arguing since that is not what anyone (myself nor Eric) is saying at all.

You can have an Angel in a small tank without a skimmer of course. There is more than 1 way to oxygenate a tank. Just because you can keep a whole angel in a small tank without a skimmer doesn't mean that skimmers don't oxygenate tanks.

[Bob I]

Thinking about it I have come to realise that there is surface agitation inside a skimmer. If the water that has been agitated gets into the tank, I will have to graciously admit I was wrong.