Siphon for diy aio

[treesprite]

I was thinking of doing an infinite siphon for my 29g diy AIO, so I can take out the Maxijet I have pumping water from sump side to display side. I can't use macros with the pump in there, and am wondering if a siphon way to move water from side to side would be enough circulation in that size tank to get me through a power outage without needing battery things. 

 

 

 

[DaJMasta]

While you can use a siphon to transfer water, you won't be able to transfer it back unless you've got somewhere to drop it to (a sump or other lower tank in the system), so you're going to need something to push the water one way or another.  A wide diameter pipe just brought to a siphon and left there would connect the two bodies of water, but they will only barely come in contact with each other, as it would rely on osmosis or movement through the pipe to mix the sides.  You also run the risk of breaking the siphon if bubbles accumulate in there.

While it is battery based, probably the simplest temporary solution would be an air stone and pump on a backup (and air pumps with integrated batteries are out there).  A small volume of air keeps the water moving and aerated and holds off problems for a good many hours even in absence of light, heat, etc.

[treesprite]

4 hours ago, DaJMasta said:

While you can use a siphon to transfer water, you won't be able to transfer it back unless you've got somewhere to drop it to (a sump or other lower tank in the system), so you're going to need something to push the water one way or another.

 

A wide diameter pipe just brought to a siphon and left there would connect the two bodies of water, but they will only barely come in contact with each other, as it would rely on osmosis or movement through the pipe to mix the sides.  You also run the risk of breaking the siphon if bubbles accumulate in there.

While it is battery based, probably the simplest temporary solution would be an air stone and pump on a backup (and air pumps with integrated batteries are out there).  A small volume of air keeps the water moving and aerated and holds off problems for a good many hours even in absence of light, heat, etc.

 

It is an AIO, so the display and sump are the same tank. Right now I have a Maxijet sucking water out of the sump side to put into the display side, but why waste electricity if I can use a siphon to do the same thing (aside from aesthetics) ? 

 

Only the siphoning end of the pipe or hose would be under water (in the sump side), otherwise the siphon won't happen from sump to display. So - important in the event of a power outage - the outflow would add at least a tiny bit of oxygenation by breaking the water surface in the display, and the flow back over the wall into the sump will add another bit of oxygenation breaking the water surface. I don't know if that is adequate oxygenation for anything near the bottom of the tank if there is an outage for more than just a short unknown length of time (flow is another problem, but battery operated bubblers don't really add any flow either). 

Edited August 15, 2023 by treesprite

[DaJMasta]

If you don't have a difference in the height of the water line on either side of the siphon, nothing will flow, a siphon is just trying to equalize the water pressure on either side.  It will make a water-to-water collection, which if there was a difference in oxygen level in one area would slowly equalize with the other side through osmosis, but I wouldn't guess this effect would be significant, especially when compared to the normal gas exchange with the surface.  Leaving a siphon in the two chambers will also slightly decrease the flow over the overflow, since when powered, the siphon will take some portion of the water coming out of the display (may not be noticeable, but could be a pathway around the teeth for small fish that would otherwise be kept out.)

You would be surprised at how much water some air bubbles can move, and just the extra surface agitation and contact time as they rise makes a noticeable different in oxygenation.  Even a few bubbles per second at a depth of more than a few inches will create an upwelling that draws in water from below and pushes it towards the surface.  The volume isn't huge, but the constant circulation past the surface of the water really improves oxygen levels dramatically.  If you constrain the path of the bubbles in a tube, you've got an airlift pump, which can give you some head height above the surface or just make a more noticeable flow entry point at the bottom.

In my tank, I have about 1:15 or so before the fish start panting if all the flow goes off.  Even a single airstone powered by a modest pump increases that duration to more than 6 hours with nothing else, and were I to measure it, I wouldn't be surprised if it would manage 12 hours or more.  Corals wouldn't be happy, the tank would cool down - there would be other problems - but oxygenation (and removal of CO2) wouldn't be one of them.


A good demo of the flow an airstone can create is done at night.  Turn the pumps off, let the current settle, put in the airstone, and look through with a flashlight.  The glint of the light off the particulate in the water should show you the flow pretty reliably and while it's not powerhead levels, it is noticeable.