Got Oxygen?

sepulatian

sepulatian

Moderator
Originally Posted by usirchchris
http:///forum/post/2664757
I realize a protein skimmer has a function, I was merely speaking in terms of oxygination. Even if a protein skimmer does spin the bubble...the bubble still travels to the top and then breaks. You may have finer bubbles but the end result is the same regardless of travel is it not? or am I missing something? Is there a difference of vertical or horizontal agitation?
There is a very big difference. Horizontal agitation goes throughout the tank. Vertical goes straight up. Big difference there.
You have to have movement in the tank. Think about this. Picture your tank. Air bubbles go straight to the top. Power heads and a skimmer moves the water, and the oxygen, throughout the tank. The bubbles from an air stone do not go anywhere but their path to the top.
 
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usirchchris

Guest
Originally Posted by sepulatian
http:///forum/post/2664767
There is a very big difference. Horizontal agitation goes throughout the tank. Vertical goes straight up. Big difference there.
You have to have movement in the tank. Think about this. Picture your tank. Air bubbles go straight to the top. Power heads and a skimmer moves the water, and the oxygen, throughout the tank. The bubbles from an air stone do not go anywhere but their path to the top.
Ok I gotcha, so if I am able to hook something up so that when my power goes out it blows the bubbles...such as a powerhead...then my oxygination is achieved? To put another way...the pumps are oxyginating but only at the very top of my water, so I need something to disperse it throughout the tank...Thinking I could buy one of those computer back ups to run a single powerhead? Perhaps someone has some other ideas on this. I would probably do a generator aside the fact that for any reasonably priced generator I would have to be home to start it. This is pointless to me as I can use a five gallon bucket to get the water moving and I save myself 400 dollars...it is in my absence that I am concerned.
 
nigerbang

nigerbang

Active Member
Originally Posted by prime311
http:///forum/post/2664738
Protein Skimmers also oxygenate.
This was posted on my Local Reef club..
about the gas exchange of a skimmer vs a fan blowing on the water surface
"Using platypus's numbers of 0.5mm bubble size (probably too big, but just makes my point), that's 4/3pi(0.25^2) = 0.261 cu mm = 0.000261mL of air in each bubble. Using the same theoretical numbers for skimmer performance, that means that the water in the skimmer was exposed to 88.9 liters of air over one hour. A standard size fan blowing over a sump measures about 15 cu ft / min (I've posted this long ago on these forums when I borrowed an anenometer.), then that's 424 liters of air each minute over the surface of the tank, compared to 88.9/60 = 1.48 liters per minute.
So, by doing the math based on volume of air exposed, there's 286 times as much air being exposed to the surface by that fan than by the skimmer in the same amount of time. Granted, there's inefficiencies in the fan over the water, but my point is still this - numbers aren't everything.
The only true way to test this would be to use a dissolved O2 meter and check the effluent of the skimmer vs. a tank with only circulation. Or, better yet, the same system without external factors (livestock), with and without the skimmer for a 24+ hours."
 
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tizzo

Guest
USIRCH, I skimmed, so if Sep got it then ignore me.
My reference to agitating the surface it...
Here's an example.
If you take a piece of thread and pull it straight across 10 inches, then your thread is of course 10 inches. But if you wave it up and down over 10 inches, then when you straighten that thread out, you may have 20 or more inches of thread.
That is an example of a larger surface area, The 10 inches stays the same, but the water to air contact space is greatly enlarged.
Bubbles popping don't really disturb the surface to me, unless your tank is at a rolling boil, lol. And the salt creep it causes, just isn't worth it to me.
 
bgbdwlf2500

bgbdwlf2500

Member
im just going to post what i know...on my freshwater tank if i turn my air pump off my fish die within 8 hours...it has a canister filter on it that does not break the surface...is SW different? seems to me the air pump does more than enough
 
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tizzo

Guest
For saltwater, air bubbles are more of a disadvantage than an advantage.
Trapped air inside the fish for one, incredible salt creep for another, and those little bubbles are not absorbing into the water very much at all. The part that floats to the top well, floats to the top. It isn't absorbed into the water.
The surface agitation it creates is incredibly mnimal. So minimal in fact, that you don't even see ripplage on the glass.
 
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usirchchris

Guest
Originally Posted by Tizzo
http:///forum/post/2665770
For saltwater, air bubbles are more of a disadvantage than an advantage.
Trapped air inside the fish for one, incredible salt creep for another, and those little bubbles are not absorbing into the water very much at all. The part that floats to the top well, floats to the top. It isn't absorbed into the water.
The surface agitation it creates is incredibly mnimal. So minimal in fact, that you don't even see ripplage on the glass.
Ok let's put my bubbles aside...for the moment I will concede. What is an effective method of oxyginating the water for less than the cost of a generator in the event of a poweroutage...or what could I couple with my bubbles so that my fish will remain safe. As of yet, this spring, the longest the power has been out was three to four hours...being such a short time I can't really justify on my end that my pumps did anything but give me a false sense of security. Does anyone do anything aside a generator?
 
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usirchchris

Guest
Hmm seems like a good intentioned idea, but the run times are mere minutes even at half use. Not much would be gained if in an 8 hour power outage. Perhaps if I am just using 1 small powerhead I could get an hour or two out of them
.
 
sly

sly

Active Member
I can get about 8 hours out of mine... but I only have the main system pump and the skimmer pump on it. They are not big enough for heaters or lights.
If you "daisy chain" several batteries, you can get a few days out of them.
 
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usirchchris

Guest
Originally Posted by Sly
http:///forum/post/2666136
I can get about 8 hours out of mine... but I only have the main system pump and the skimmer pump on it. They are not big enough for heaters or lights.
If you "daisy chain" several batteries, you can get a few days out of them.
8 hours would be perfect...you mind posting which one you have? or at least how many watts. Thanks in advance.
 
scrombus2

scrombus2

Member
One point that was barely touched on in this thread is this: What matters to fish is the amount of DISSOLVED oxygen in the water. A water molecule is 1/3 oxygen, but since it's locked up in the H2O molecule, it's useless to fish. Oxygen is very soluble in water, as the oxygen in the atmosphere contacts the surface of the water, a portion of the atmospheric oxygen dissolves in the water. The rate of this dissolution depends on several factors, the most important factor being surface area exposed to air. The second most important factor is the amount of oxygen already in the water, the 'saturation'.There's a threshold where the water will not absorb any more oxygen, no matter how much water is exposed to air. While an airstone in the tank causes problems, there's a tremendous amount of water being exposed to air in our skimmers. Exponentially more than just the surface exchange at the top of the tank, no matter how much surface agitation is taking place.
 
sly

sly

Active Member
Originally Posted by usirchchris
http:///forum/post/2666170
8 hours would be perfect...you mind posting which one you have? or at least how many watts. Thanks in advance.
Its an APC SmartUPS 1000VA power supply. They come in handy when there are power outages. Last night the power went off for an hour but the tank didn't miss a beat. You can add more battery packs to them to get more run time.
I have mine hard wired into the house. I don't recommend this unless you really know what you are doing. One of the circuits in my house goes to most of the overhead lights... None of the wall outlets are on this circuit. This is important because you eliminate the risk of increasing the load on the UPS by having something plugged into the wall when the power goes out.
Whenever the power goes out I still have the pumps running on the tank, plus I can turn on just about every light on the first floor of the house, including the outside lights. I measured the amp load of every light turned on at the same time to make sure it wouldn't overload the UPS and everything works fine. I then removed all the incandescent bulbs and switched everything over to CFL bulbs just to make there even less of a load on the UPS.
Like I said, we had an outage last night and I could still turn on the lights, surf the internet and know that the fish were going to be ok.
 
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