Thanks for the clarification Sam,
I agree if the main tank is the problem a q-tank wouldn't do much. I guess I think no system is perfect, so even after I quarantine the fish there is no harm in the hobbyist doing it again.

[quote="StirCrazy"]I could prove that is wrong, it has something to do with surface tension, and if indeed there was gas exchange the tiny bubbles in a skimmer would never reach the surface because they would be absorbed. Unfortunately I can't remember where I read that, and I don't like unsupported statements, which is something you don't appear to have a problem with. I am also somewhat tired of it. you seem to feel that I make this stuff up. You will happily argue black is white, and vice versa. I just can't handle these constant arguments. :rolleyes:

for oxegenating water there are 2 main methods, aspirating, and agitating....

Agitators use a small motor to spin a paddle which is in the water. The paddle splashes the water, which adds oxygen and removes carbon dioxide.

(skimmers)Aspirators also use a small motor, which spins a small venturi device. Air is pulled down through the shaft and exits the venturi underwater, causing a draft of bubbles.

Agitators are the best choice for heavy stocking loads because they transfer "more" oxygen than aspirators.

Aspirators are a good choice for smaller stocking densities, and they are much quieter than agitators. And less messy...

this is fact, Bob is corect, but skimmers do the job for us with our low stocking densities....

Oxygen exchange at the water surface is "best", and oxygen exchange underwater is "good"

this is why in aquaculture the utilize foam heads(mazei)(beckett) at the surface and not underwater

I'm not suggesting that bubbles underwater increases O2. Its when the bubbles burst at the surface of the water that oxygenates the water coming out of the skimmer. I think I'll look for a dissolved oxygen meter on Ebay and do some experiments and see what kind of results I get without sacrificing the lives of my fish. :)

actualy it is because they will not work underwater and by having it above the water you get the O2 from the bubbles and you ALSO get the O2 from the resulting splashing.

Bob, I am not saying the skimmer is a perfect airerator as then like your example "the tiny bubbles in a skimmer would never reach the surface because they would be absorbed." kinda think of the skimmer of using a buldozer to dig a hole for a tulip bulb. hit it with brute excess and get a little. infact when it comes to skimmers becketts are very inefficient compared to counter current skimmers but if you are only 30% efficient but process 1000% more water in the same time period, you get a better result.

for what its worth I only use the trickel of water from my aquaclear to add O2 to my fresh water tanks and there is very little surface movement.

Steve

this is why in aquaculture they utilize foam heads(mazei)(beckett) at the surface and not "venturi"underwater


I missed that special word....lol
I do understand that a beckett or mazzie wont work underwater....

I am pretty well surprised that most people here, including people known to have excellent tanks, don't quarantine. Seems like the cost of one or two dead fish would pay for a q-tank setup.

trilinearmipmap - thats how I feel too.

Are you assuming that all the people who don't quarantine have dead fish as a result? That would be an incorrect assumption.

Many of my fish are five years here. However, I certainly think if QT works for you, you should do it. :biggrin:

No Emily...

what I am thinking is that I have several hundred $ worth of fish in my tank. My next fish will probably cost me more then $20.

If I were to skip QT on that $20 fish and he happened to introduce ich or something nastier to my tank and I lost all my fishes... I would kick myself really hard several times over for not spending $75 on a QT tank and actually using it.