Preventing a back siphon to sump?

[seattlerob]

MarineGirl: I also have a drilled overflow, drilled return & lock line. I did not drill any sort of siphon break. The siphon break for me happens when the water drops below the ends of the lock line. Once that happens, they suck air & thus break the siphon.

In other words, when everything is running, my waterline is approx 1" higher than where the ends of the lockline are. If my return pump stops, my water backflows via lock line/return lines into the sump until the water level drops 1". I could angle the lockline a bit different if I wanted less backflow. Honestly, I could position the lockline returns to be higher than where they enter the tank, so even if I had a siphon break drilled it wouldn't matter.

On my sump, I have a marker line that is my max fill line. I know that there's enough room still in the sump to handle the overflow. Regardless of whether you drill a siphon break, etc, this is the key part. Turn off your return pump to simulate a power loss & make sure you have enough room in your sump to handle the backflow. Make a mark where you want to fill to. (That is also where you top off to).

hth,
rob

 

[CoolUsername]

MarineGirl411,

I don't have loc-line, but am familiar with it. I personally think WarrenG's solution makes the most sense. You don't want to "have to" position the outlets of your loc-lines in such a way to minimize back siphon. That's not what they are for. The have a significant degree of flexibility to place flow where you want it. Keep them

That being said I would place the return bulkhead as high as you can. The higher you place it the stronger the tank. First drilling a hole weakens the glass - maybe not much but it does make it is weaker. Do you want to put 0 PSI on that weak part or 1PSI(you can get almost 1psi in a two foot deep tank)? the deaper you place the hole the more pressure on it. I wouldn't worry about the glass breaking anyways, but technically it is stronger higher. I wouldn't worry about this. A hole in any height is going to be fine in an aquarium. You just don't want to get too close to an edge of a pane.

So that advantage you gain by putting it higher is your siphon break is easier to implement. Drill a hole as near to the bulkhead as possible. You can drill a hole into loc line. Drill in the first link away from the bulkhead, unless there is a nearer place. Make sure that the hole wont get "sealed" no matter how you manuver your loc line. Then if the return siphon volume is still too much for you sump, try WarrenG's tubing idea.

 

[MarineGirl411]

Sounds great. Thank you so much everyone. I was afraid that the more holes I drill the weaker the glass would get. That's why I didn't want to go with the Calfo Overflow idea. It would also block flow from my sea swirl. If I do place the loc line higher, it might only back siphon a little. I will still install a check valve. I will test everything first to simulate a power outage. That is a great idea. How do you determine how much water should be in your sump? I've seen some with water almost all the way to the rim. My sump will also house a refugium. Thank you for all the help guys. It has really helped me a lot.

 

[toastman]

Just be carefull with check valve only protection, over time the insides of your pipes will get some build up and the check valve may not function fully. I would install the check valve with unions so you can take it out and clean it completely every 6 months or so.

 

[devildij]

hey pooch sorry about that short answer i wuz kind of in a hurry right then

so you can see it here http://img65.exs.cx/img65/1820/overflow5lh.jpg
pleez post any questions by a PM

 

[pitbullpooch]

<a href=showthread.php?s=&postid=8156501#post8156501 target=_blank>Originally posted</a> by devildij
hey pooch sorry about that short answer i wuz kind of in a hurry right then

so you can see it here http://img65.exs.cx/img65/1820/overflow5lh.jpg
pleez post any questions by a PM

got yea now. im just not good without a picture. i use to be a machinist so i cant figure out anything without a blueprint or some kind of diagram lol. thanks for clearing that up.

 

[CoolUsername]

I don't believe MarineGirl is looking for info on a siphon overflow. She's planning on drilling the tank.

 

[MarineGirl411]

Yup exactly. I am going to drill the tank for my overflow. I think I am going to place the return lines as close to the surface as possible to prevent the overflow into the sump. I will test it and if I need to drill a hole I will. Thank you all so much. =)

 

[MarineGirl411]

I mean to prevent a back siphon. LOL sorry

 

[bassnman11]

siphon break.

siphon break.

Do not use the check valves they sell at Lowes or HD. They have a spring inside that will not last long. You can get check valves that use gravity to close. I got mine from Foster & Smith. As far as drilling holes for the siphon break, you can use more than 1 hole per pipe. I stick a paperclip in the holes when I do water changes.

 

[MarineGirl411]

okay I guess I will have to order it from Drs Foster and Smith.