# Air stone in sump



## castle (2 Jan 2021)

In an effort to get more (gentle) flow around my 'main' tank and to hide that heater/hob, I'm planning on creating a wet/dry sump with spray bar return. I've bought the sump and pipes  

I was thinking to further boost the chance of nano bubbles in the water, I could put an airstone in front of the return pump to suck up some small bubbles into the aquarium, but I'm worried that they could build up in the return pipes arch over glass. The airstone would only be on for say, 8 hours after lights off. 

I'm kind of aware that the wet/dry will increase oxygen saturation in water far better than these bubbles, but my thinking was these bubbles would also help?


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## foxfish (2 Jan 2021)

I can’t think of any benefits myself but you can do so if you wish.
Just bear in mind that if you are running a genuine 4-5 tank volume down the overflow every hour then you are exposing the contents of you display to air 5 times every hour and I very much doubt if you will need more oxygen.
However if you did want more oxygen then a trickle towed in the sump will do that for you.
The main issue I see with pumping air into the return pump would be noise and cavitation.... it is one thing running a few bubbles a second of C02 into the pump but running an air stone may effect the pumps performance?
Anyhow you can give it a go if you want to and see what happens!


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## Mr.Shenanagins (2 Jan 2021)

You should be more concerned about CO2 than O2. The overflow itself is all you need. I inject about 4-6 bubbles a second 3 hours before the lights come on with my sump just to get a green drop checker. O2 is not something to waste your time with I promise you you’ll have enough of it running a sump.


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## castle (2 Jan 2021)

I think, after some thought - and a fair bit of googling; that the airpump might be unnecessary. 

I don't run CO2, so that's not an issue for me.


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## dino21 (3 Jan 2021)

Hi,

I would first ask why are you wanting a more gentle flow ? are the fish having problems or the plants being buffeted too much ?
 If your  filter / pump too strong, most devices have some means for regulating the flow, or direct the flow onto the glass so it helps disperse it more ?

Re the Oxygen, what makes you think you need more in the water ?   If you have fish in there are they gasping on the surface or being very lethargic .
How many plants do you have in there , are they growing well and can you see any signs of "pearling" indicating the plants are releasing plenty of oxygen into the water.

As said, to much agitation , will drive the Co2 out of the water, the very food the plants need to photosynthesis and produce  Oxygen.

Do not know the size of your tank, but for smaller tanks Sumps can be, imho,  more trouble that they are worth and if the design is poor  lots of unwanted water noises and potential leaks.


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## zozo (3 Jan 2021)

What about a venturi nozzle to the spray bar?  It's a lot quieter and doesn't consume energy... Or use a y split duckbill outlet instead with the venturi nozzle in front of it to make it even more sufficient.


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## castle (3 Jan 2021)

@zozo I've been designing one to go inline on the return of an external filter most of this morning 

@dino21 The fish I keep do not like flow, so I have a balancing act. I am trying to make sure I have maximised oxygen saturation in water so that my waste breakdown isn't limited. I don't have any science to back up my issues in my tank are oxygen based, but I don't think I can add too much. I have too many plants, they're all growing, they're all low-tech (see here!). I'm wanting to make sure, that any waste is being processed.

As I don't add Co2, I can't see that surface agitation will have much effect on dissolved Co2 as I guess it will be at an equilibrium with the air?


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## zozo (3 Jan 2021)

castle said:


> I've been designing one to go inline on the return of an external filter most of this morning



It's actually really simple to make one, you would need a bottleneck to create the pressure difference. Then all it needs is a small hole behind or in the middle of this bottleneck...

Using a hose connector like this already makes the bottleneck...



Then a small hole plugged with a 4mm airtube valve, like this one.




Making the hole the correct size it fits snuggle enough to avoid the use of any sealant.  

If that doesn't work they can be bought from JBL or Juwel etc.


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