Battery operated pump - back syphon?

[Armando]

I installed battery operated pumps with airstones into the tank but i'm wondering if there is a possibility of a back syphon drying the tank. Do I need to bother using a check valve?

 

[synchiropi]

I would just add it. Apart from some reduction on the airflow what are other possible drawbacks of having a check valve?

I have had some unexplainable back syphon experiences before. Just think its an inexpensive way for some added safety.

 

[~Flighty~]

Assuming you are having the tube go over the tank wall I wouldn't think it could fill with water to start a siphon, but to be safe, could you mount the pump above the water level?

 

[Greg Hiller]

>could you mount the pump above the water level?<

That's what I do, AND I have a check valve. I built some brakets out of acrylic to hang then pumps off the back of the tank.

 

[Armando]

can't hang them above water so i went to the store and got a couple of check valves. installed them and unplugged the air pump to test how much air restriction. for whatever reason GFCI tripped. sump overflow. another flood. i'm about to throw the tank out the window.

 

[montec24]

I had one fall of the shelf it was on, the hose unhooked at the pump, stone stayed in the water..... 25 gallons of water on the floo

 

[gurumasta]

i just ordered a few of these battery back up pumps and im wondering where you get the check valves for the airline tubing, and what other measures people are taking to prevent back syphon. thanks, derek

 

[ReeferMedic]

i just ordered a few of these battery back up pumps and im wondering where you get the check valves for the airline tubing, and what other measures people are taking to prevent back syphon. thanks, derek

You can get them pretty much at any lfs. The only reason I haven't hooked mine up is I don't trust them 100%. I'm trying to figure out a way to mount them above the water line and out of sight, and I will still use a check valve. They will definately create a siphon if the power goes out and they go on then shut off when the power comes back on..........

 

[~Flighty~]

can someone explain how the siphen starts? In other words, how does the water level in the airline get over the tank wall?

 

[gurumasta]

can someone explain how the siphen starts? In other words, how does the water level in the airline get over the tank wall?

it will create syphon because the outlet end is submerged and there is air being pumped through it. once that airflow stops, it will work with gravity and travel back through the airline towards the air pump. this backward airflow will create a syphon.

 

[ReeferMedic]

can someone explain how the siphen starts? In other words, how does the water level in the airline get over the tank wall?

You get back pressure(not sure if that's the right word or not)when the air flow stops, then the water starts flowing. It doesn't take much with a thin diameter tube. You can experiment with it. take a piece of airline tubing with an air stone attached so it will stay under water and place that end in the tank. Make sure the end that is not in the aquaruim is below the water line. Blow into the tube so you get air bubbles in the tank. When you stop, you should get a siphon of water coming out of the tube outside the tank. The deeper the tube inside the water, the easier the siphon will be to start..........

 

[Mini4x]

capillary action?

 

[Conlius]

well it could be worse....when i reduced my return line from two to one on my mag 7, the rubber tube that was cemented into a pvc fitting shot out and sprayed all the water in my return compartment directly up at the sump lighting...my "fake" actinic ballast started to smoke, i only know this because i came home to a smoke filled room, and the ballast had basically melted itself....yes....i could have burned down my apartment complex...booyah to that

 

[~Flighty~]

So it is the momentum of the water rushing back up the tube carries it higher than the tank wall. So you should be able to prevent the back siphen by just making the bend in the tube a little higher -putting it over a hook on the hood or something.

 

[nitrofish]

ive had a syphon start with my airstones before. its deffinitly something to watch out for.