# multiple air pumps on a single airstone



## evilhorde (Feb 3, 2012)

I have a 4 output air pump in my tanks feeding 4 six inch round airstones.
I am wondering if I can connect two of the outputs to one airstone. 
Would this work to increase the bubble output of a single airstone?
Would I need to use two backflow preventers to keep the air from bleeding back into the opposite pump output or can I just use a 'Y' and run them together?
Will this have a negative impact on the longevity of my air pump?


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## GeToChKn (Apr 15, 2011)

How much blasting do you want from an airstone? With a good pump, I have to turn down my airstones because they blast water right out of the tank, so if you're not getting enough bubbles from a single airstone hooked up, I would either look at replacing the pump or airstone. I have the dual output whisper pump and can run 4-6 devices off the 2 outputs including airstone, sponge filter, UGF filter, breeder box.


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## Merth (Sep 9, 2012)

simple answer is yes you can use a Y and only need 1 back flow preventer on the leg. It wont affect the life of the pump if you have that slow a flow anyways.


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## evilhorde (Feb 3, 2012)

GeToChKn said:


> I would either look at replacing the pump or airstone.


Everything is relatively new. I have the 6" airstones under a layer of sand and it only seems to be pushing air up over half of the airstone.
My main motivation here is that I want to discontinue using two of the airstones and I don't want to block off the remaining two outputs, nor do I want to go buy another new pump. Then I got thinking that if I could double the output on the remaing two, I could use them as a fence to keep the floating plants down at one end of the tank. Two birds, one stone sort of thing.


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## evilhorde (Feb 3, 2012)

Merth said:


> simple answer is yes you can use a Y and only need 1 back flow preventer on the leg. It wont affect the life of the pump if you have that slow a flow anyways.


And since my pump sits a couple of feet higher than the tank, I don't need any backflow preventer at all?


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## dmagerl (Feb 2, 2010)

I have a whisper 60 pump with 2 outputs. I Tee'ed the two outputs together. 6 months later I had to buy two new rubber membranes. I cant say that connecting the two sides together was the reason for the failures but I was really po'ed.

Connecting them together depends on the phases of the pumping mechanisms. For example, take two pumps. If both are pushing air at the same time, you'll get twice the pressure if you connect them together. But if one is pushing and the other is pulling air, then the two pumps should cancel each other out and you'll end up with a weaker flow than if you used just one output.

Of course, if the outputs are just multiple taps on just one pump, it makes absolutely no difference if you Tee them together or cap them off.


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## evilhorde (Feb 3, 2012)

I've t'ed them together and I am definitely getting more output on both. One is a complete solid flow of bubbles across the 6" and the other is not as complete but the bubbles are larger. I guess time will tell on the longevity issue and I'll see in a few days if it works as an effective plant barrier.

Thanks.


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## Merth (Sep 9, 2012)

And correct on the backflow preventer not needed...tho I always use one just in case. Murphy's law and all my luck hose would come off pump and empty tank on floor


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## ProndFarms (Sep 3, 2012)

I would be cautious doing so. Simply because you are adding more "pressure" to the hose does not mean that more volume will come out.

Think of it in terms of a garden hose. While you can certainly increase the "pressure" of the water coming out, the volume of water that is expelled is roughly the same, perhaps even less.

I don't know what type of pump you are using so I would agree with the others and caution it. I have done it, but those membranes probably will wear out.


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## PlantedRich (Jul 21, 2010)

When you set up an air pump that uses a diaphragm, it is always a good idea to check the specs on how many air stones it is designed to power and what size. If you have a pump with several outlets it is good practice to leave some way to vent off the excess. 

This is what I find when that type air pumps fails. There is often a metal arm which swings in/out in time with the sixty cycle AC power. The diaphragm is attached to this arm so that it is pulled and pushed to force air through a small flap or one way valve. The connection is often a small bolt through the diaphragm. If there is back pressure from not enough places for the air to escape, it creates a lot of stress at the point of attachment. This makes the arm and bolt move but the diaphragm can't move as it should. Over time this stress causes the diaphragm to tear near the bolt and the pump fails. You may have found used pumps that seem to work and blow air when out of the water but if you put an air stone down into the tank it stops? That is because the diaphragm moves okay but air escapes through the tear when it has to work against the water pressure. 

Good policy is to let the excess have a way to escape to avoid tearing the diaphragm.


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