reverse syphon on pump line causing sump to overflow

[OttawaReefer]

I had a small power outage this morning and my sump overflowed all over the living room.  Four bath towels later I had it cleaned up and started to check to see what caused it.

I unplugged the pump and watched the overflow drain until it stopped but the water in the sump kept rising...and quickly.  I checked the overflow line again and there was no water coming down, so the only place could have been from the pump line.  I guess as the pump shut off a syphon started in the pump line and just kept bringing in water from the tank.

I'm planning on changing the tube into the tank with a solid PVC tube and put some holes in the top as well with the idea that as the water level drops those holes should break any syphon.  I've attached a quick drawing.  Can anyone see why this wouldn't work to break that syphon?

[attachment deleted by admin]

[veron]

put a 90elbow at the top just under the water surface. once the power is out the water will stop flowing and you'll have a syphon break.
holes in a pipe will just get clogged at the wrong moment [snail, algea etc.]

[OttawaReefer]

put a 90elbow at the top just under the water surface. once the power is out the water will stop flowing and you'll have a syphon break.
holes in a pipe will just get clogged at the wrong moment [snail, algea etc.]

So.....instead of having the PVC tube go that far down in the tank I should just cut it right below the water level?  Not sure what you mean by having just a 90 elbow.

Maybe like this:


   |---
   |   |__
   |
   |
   |


Don't laugh too much at my artistic skills.

[veron]

you could just cut it and have the flow straight done or add the elbow [as in your pic]
to have the flow across the tank

[OttawaReefer]

Thanks.  I'll make sure to get this done today.

The wife loves the tank but wasn't so impressed with me screaming for her to thow as many towels as she could find down the stairs.

[Hookup]

Thanks.  I'll make sure to get this done today.

The wife loves the tank but wasn't so impressed with me screaming for her to thow as many towels as she could find down the stairs.

LOL number of times i've done that.. well the wife went and bought me special tank-towels... 

[Consigliere]

All you need is the holes in the pump line like you are showing in your drawing.  As soon as the water line drops below the first hole, air will enter the line and break the siphon.

[mikerobart]

+1 siphon break holes

Pretty standard stuff I think on many overflows

[veron]

syphon holes are not fool proof, many forget to clean the algea buildup and snails can park on the holes. best way is to have the elbow just below the surface or cut the pipe just below the surface.

[OttawaReefer]

The wholes seemed to have worked.  I tested it twice and both times after hitting the first hole it stopped the syphon.  Now I will have to explain to the missus that just a little hole would have prevented the flooding.

[lost_at_sea]

The wholes seemed to have worked.  I tested it twice and both times after hitting the first hole it stopped the syphon.  Now I will have to explain to the missus that just a little hole would have prevented the flooding.

Until the next time when a snail decides to park overtop of it Murphy is a (blank)

[mikerobart]

It is true a snail could block the hole, but can always do more than one for peace of mind / fashion a snail guard of some sort or use airline tubing.. a lot of different ways to deal with this if you feel like it.

[Canoe]

syphon holes are not fool proof, many forget to clean the algea buildup and snails can park on the holes. best way is to have the elbow just below the surface or cut the pipe just below the surface.

I've seen many posts at Reef Central about relying upon such holes, then cleaning gets hap-hazard, then you have a failure and a flood, and dead things, and a mess, and maybe flooring or structure to replace. You're on holidays and the neighbor/friend/relative/service comes by once a day to feed/check...

Anyone can engineer something to work, but what happens when one or more components fail? What is the resulting behavior?

Engineer for failure...
... what happens in the system when this fails?
... what happens in the system when this and that fail?
etc., ...

Sure, have the siphon-break holes & mini air/return line feeding to the tank, but have the return just below the surface to limit the amount of flow-back if the siphon-break fails. What else?

[beertech]

 I drilled 2 holes, and have the sump run at a low level so it can contain all the water if the holes were plugged and the pump syphoned. It can only go as far down as the end pump return tube.

[Luke_L]

go to home depot and get a one way flow valve, the plastic ones should cost about 5 bucks
put it anywhere on the line in or outside the tank.  that way you wont have any issues with sump overflow.

That or get a larger sump that can handle the overflow.
rock on
Luke