Air Pump vs Water Pump

I believe that using diaphram air pumps to oxygenate res water may not be the best way to go. This opinion is based on many years of experience in setting up and maintaining reef aquariums and researching techical information relative to the health of delicate corals.

As I understand the air/water exchange principles, the actual gas exchange takes place at the surface where the air and water come in contact. The agitation of the water causes an incease in the volume of oxygen in the water. In other words, the bubbles rising through the water column add little to nothing to the exchange. It is at the surface. The greater the surface area the more exchange activity you will have. In the ocean, the highlest levels of oxygen are at the surface and diminish rapidly as the depth increases.

Using a small water pump to create surface turbulance accoumplishes the same task (surface agitation) without he noise of a vibarating air pump and these small pumps last for years. No airstones to clog, no noise, and no tubing to route.

Other opinions?

Very good observation and you are correct. The only problem with using submergible pumps is that they heat the water a bit as well. Heating the water is not a good idea, cool water can hold more oxygen then warm water will.

The more air bubbles you have the more agitation you can produce with the bubbles and thus the more oxygen you can make.

There are many growing styles that use the capillary action from the air stones to provide water the roots. They are a viable way to grow hydroponics for many starters.

So you must consider balancing the air vs. the heat. You have observed I assume; it's the falling water that reproduces the capillary action and oxygenates the water. That can make noise as well (the falling water fall) so if your goal is to quit the noise from an air pump then maybe another pump may not be the best way to go. They do have many quit air pumps but you also make a great point as well.

It depends on your growing style and your choice of methods you use.
If you switch to the outside pumps to save the heat then you have the sound of the water falling back into the rez to deal with.
All of the above methods can and do provide plenty of oxygen for the plants, One thing we have over fish thanks is that for a proper hydroponic grow you change out the water and nutrients every 7-10 days anyway so what you are doing with the air stones is to not only water the plants if that is how you are growing it also does oxygenate the water.
So give some more thought before you toss those air stones in the trash.

Also, i belive i read somewhere, and i can def say that it is true becuase i use organic nutes, apparently the extra oxygen being pumped into the water, does something to the dissolved nutes, i end up with alot of crap at the bottom of my res that doesnt mix. Only with organics. But to my unserstanding if you dont have a problem with the nutes in the res then a airation method in the res is a very good idea. Also you need to understand that the air pump is directly putting the oxygen at the bottom of the res, allowing the oxygen to attach to particles in a matter as it rises to the top. in normal condition where there would be no air comming from the bottom, the only place it can come from is the surface.

And when it reaches the top, there are manny bubbles that attribute to putting oxygen in the water at the surface, so having no bubbles at the surface compared to having them there. I dont see a disturbance in the surface fo the water having to much more of an effect ot the oxy levels.

Zandor & Jack, thanx for the comments. I did fail to consider the heat because it isn't a factor in large reef tank setups.

I have used large airpumps to run foam fractoner systems to purify salt water and have had to change many a diaphram that always seem to fail when least expected.

Profs to all.

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Originally Posted by JackdaWack

And when it reaches the top, there are manny bubbles that attribute to putting oxygen in the water at the surface, so having no bubbles at the surface compared to having them there. I dont see a disturbance in the surface fo the water having to much more of an effect ot the oxy levels.

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Sorry jack but I do disagree with you; it's just that physics have proven that the movement of water will produce oxygen. You are not putting air into the water from the diaphragm the air comes from the bubble action.

What you see in your organics is the sediment from your nutrients and in my opinion people who grow organics need to have a second submergible pump in their res to keep the nutrients mixed up at all times or you will get the sediment like you are saying. The action of the pump moving the water around will also provide oxygen as well. Not as much as the cascading action will but it will oxygenate the water all the same.
Itâ??s just basic science, nothing new.

No i do agree with you zandor i said or maybe it wasnt clear, that, it wouldnt put as much O in the water as a airpump. Also a good idea for mixing nutes, some fo the high power 300+gph pumps have at the nossle where the tubeing connects, some come with a piece that actually has a small hole and it jets water out aswell throught the tube so it mixes and pumps at the same time. i have one but its too big for my veggies right now when they flower it will be used.

i have run a 27 gal fishtank we used power heads for the undergravel filter. it circlates the water and adds air like a buble stone it has a deflecter but as i was setting the tank up and was getting it ready to proof i saw i could get the entire tank full of micro bubble it kinda look liked 7-up :) could a person use that type setup to mix and airate there nutes

a 2nd pump to recirculate rez is absolutely imperative when using organic hydro nutes...not so much when using something clean like 3-part.

good idea to start thread, but, I agree with Z about the heat issue. I have a helpful hint on the subject. I have found that the heat from a submersible pump isn't as damaging in a bigger deeper reservoir, requiring a higher volume of solution. also. I use 110gph pumps, and they don't generate as much heat as bigger...say 256 or 500+.

one last note. You can also balance the heat issue by have a 15 minute off time each hour. I didn't see a loss of growth when I did this, but my rez cooled down to tolerable levels, due to pump cooling down each hour.

hope this helps...It's late. peace

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Originally Posted by JackdaWack

No i do agree with you zandor i said or maybe it wasnt clear, that, it wouldnt put as much O in the water as a airpump. Also a good idea for mixing nutes, some fo the high power 300+gph pumps have at the nossle where the tubeing connects, some come with a piece that actually has a small hole and it jets water out aswell throught the tube so it mixes and pumps at the same time. i have one but its too big for my veggies right now when they flower it will be used.

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I guess I read it wrong or just miss understood you dude....sorry about that my bad.

Latewood good idea having the mixing pump on a timmer to help with the heat. :D

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Originally Posted by Crusinjimbo

As I understand the air/water exchange principles, the actual gas exchange takes place at the surface where the air and water come in contact. The agitation of the water causes an incease in the volume of oxygen in the water. In other words, the bubbles rising through the water column add little to nothing to the exchange. It is at the surface. The greater the surface area the more exchange activity you will have. ?

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You are forgetting the surface area of the bubbles themselves.

Thus, a long airstone creating a screen of many, many bubbles oxygenates the water more efficiently than sticking the end of a hose under water and releasing a single stream of bubbles.

This is of course an issue completely seperate from keeping the res well-mixed.