# Almost Flooded?



## Cardiff (Jun 2, 2008)

Well came downstairs today and checked on the fish an there was water all over the floor! It was coming from the pipe that connects to the airstone, basically you have two pipes that come from the air stones pion thing, they go into one pie, then there is a one way valve then the pipe going into the tank/stone. Thought it might be the one way valve but then thinking back it was coming from the pipe that came from the tank/stone and the pipe had come off the valve and water was just pumping out, I replaced the water an it was two bucket loads!!

Now my concern is that it came from the pipe attached to the stone so guessing it was acting like a siphon and could happen again but then hasn't happened in two years?! Just had to go out so left it off in case it happens again


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## Gaynor (Apr 10, 2009)

We had exactly the same happen - luckily we had no fish in tank, we were cycling it - we lost about 100L - on dining room carpet!!!! Not the best of things to wake up to in a morning!


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## Dj823cichild (Mar 30, 2009)

I have a question when you say pipe connected to the airstone, don't you mean plastic tubing? I'm just trying to make sense of this. Is this the airstone that is connected to your air filter or am I off in guessing this? Either ways if I'm right I have my air filter which is connected to my air stone elevated off the floor so the air flows nice and evenly and won't back up.


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## klc9100 (Apr 14, 2009)

if the air line comes off, it forms a siphon and will drain the tank. even if your air pump quits, or if you unplug it, water will be siphoned back into the pump, if it's lower than the airstone is. the check valve (one way valve) inline should let the air go through, into the tank, but not let water come back from the other direction. i'm confused.


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## Toby_H (Apr 15, 2005)

Cardiff... try to re-explain your set up taking time to spell properly and give more details... reading your post didn't give me a mental picture of your set up very well at all...

The one way valve or check valve is meant to prevent water from exiting the tank through this hose/pipe. So if water was exiting your tank through the hose/pipe that is "protected" by your one way valve or check valve, then your valve failed you.

Keeping the air pump above the water level of the tank (not the air stone) will prevent the possibility of water siphoning out of the tank and onto the floor. Water cannot siphon uphill...

Running the airline several inches above the water level of the tank will mean the water has to 'climb' higher to create a siphon. Doing this will reduce the likelihood of a siphon starting, but will still leave it as a possibility.


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## klc9100 (Apr 14, 2009)

if the air pump is one inch higher than the airstone (lowest point of the air line) it would still have to siphon "uphill". the pump doesn't have to be above water level. 1 inch, 1 foot, 1 yard, whatever - it's still "uphill" and gravity just doesn't work that way.


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## Toby_H (Apr 15, 2005)

Next time you are doing a water change... start a siphon... then hold one end of your hose on the bottom of your aquarium... then hold the other end just an inch or two below the surface of the water in the aquarium.... water still comes out of the hose...

This is not â€œsiphoning uphillâ€


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## klc9100 (Apr 14, 2009)

you are correct . . . . . if you start a siphon and then move the ends of the hose. we're talking about fixed points though. the siphon can't *start* "uphill". granted, once it starts, what you're saying is true, if you move them. but, how would the siphon start in the 1st place, if the pump end was higher than the airstone end???

edit: i apologize to the OP. i was just trying to help. whether i'm right or wrong (i think i'm right) i wasn't trying to hijack your thread.


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## Toby_H (Apr 15, 2005)

klc9100 said:


> you are correct . . . . . if you start a siphon and then move the ends of the hose. we're talking about fixed points though. the siphon can't *start* "uphill". granted, once it starts, what you're saying is true, if you move them. but, how would the siphon start in the 1st place, if the pump end was higher than the airstone end???
> 
> edit: i apologize to the OP. i was just trying to help. whether i'm right or wrong (i think i'm right) i wasn't trying to hijack your thread.


I think it's in the OP's best interest to have a proper understanding of this as well as anyone else reading along... Cardiff if you disagree I'll stop my end of the 'debateâ€™...

Also, before I go on, KLC, no offense meant and it's all in the name of clarifying a point... I'm not being argumentative and hope none of this has been taken as such...

Using the same example I made earlier... take a hose and place one end at the bottom of the tank (like where the air stone would be) and hold the other end outside of the tank about half way between the top and bottom of the tank (like where the air pump will be)... now suck to start a siphon... the tank will drain until the water surface of the aquarium matches the end of the hose that is outside of the aquarium (like where the pump will be)...

Surface tension is the culprit that allows a siphon to form in an airline by the water "wicking" up the narrow diameter of the air line... Once it wicks/climbs up over the bend in the air line it will fall downward, which starts the siphon...

Then as long as the other end of the hose is lower than the surface of the aquarium's water, weight of the water in the aquarium will continue to pull water in the end of the hose (@ the air stone) up over the lip and out the other end...

Once the aquarium's water level matches the other end of the hose (the one outside the tank) the water will "balance" and the siphon will stop/break...

Edit/Added - All in all it doesn't matter at all where the submerged end of the hose is as long as it is submerged. Because the water pressure on the submerged end is dictated by the height of the water's surface in the aquarium...

Which is why it is suggested to keep the air pump above the water level of the aquariumâ€¦


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## klc9100 (Apr 14, 2009)

OK. my bad toby. you are right. i went back and read the whole thread, and realized that i had gotten off point. what i was trying to express (and then became confused) was about the suction (siphon) getting started in the 1st place. if the air line came off of the pump, what would have started the the siphon? even so, the check valve should have stopped it, right? i see what you're saying now. i'm posting in between customers while at work.


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## Toby_H (Apr 15, 2005)

:thumb:

I figured it was something that simple You sounded like you have a decent grasp on things so I assumed one of us made a simple mistake. It's just good to talk/think/read such simple mistakes through to help others reading along to feel solid about the conclusion.

Thanks for tolerating my anal explanation


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## Dj823cichild (Mar 30, 2009)

Guess we won't hear from Cardiff or maybe he took your advices without responding.


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## Riceburner (Sep 3, 2008)

just to add...I create a loop of the tubing at the top most point outside the tank above the water line.


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