Preventing a back siphon to sump?

MarineGirl411 · #1 09/11/2006, 03:12 AM

Hi,
Sorry again, I have another very important question. I will be running a sump and I am wondering how do I prevent a back siphon durning a power outage? Won't it flood my sump? Won't it ruin my pump? Please let me know. I'd really appreciate any response. I am starting plumbing this weekend. Thank you.

Bill Z · #2 09/11/2006, 06:20 AM

drill a small hole (1/8 inch) in your return line just below the water level. The water will back siphon down to that point and then suck air.

Sailor_jon · #3 09/11/2006, 11:43 AM

Yup thats what I did, works good. I did the same on my reservoir for makeup water that sits above the sump. It sprays when the pump is one, but its all contained within the reservoir, with a lid on it.

CoolUsername · #4 09/11/2006, 07:46 PM

Yep that is what I did as well. Assuming that you have an over the back return. There are different configurations for returns. I have (and I believe Bill Z and Sailor_jon) #3.

There will be some water that drains back to the sump no matter what you do. You will need to design your sump such that this extra drainoff won't cause an overflow.

Having the water run backwards throught the pump wont hurt it.

MarineGirl411 · #5 09/12/2006, 04:35 AM

My overflow is going to be drilled onto the back if the tank. The return is also going to be drilled. I am going to be using loc-line. Should I drill a hole in the loc line? My sump is going to be around 25 gallons. I am making it this weekend and also drilling the tank. Everything is going to be drilled in the tank. CL will be loc-line and sea swirl. Then return from sump will also be locline. Please let me know if it's safe to drill that. Thank you. =)

vest0830 · #6 09/12/2006, 05:02 AM

dang, I never thought of that. I myself am going to do that also. We have a typhoon comming in this weekend, so I wanna be ready...

acwilson · #7 09/12/2006, 04:45 PM

you could also use a check valve on the PVC from the sump pump to the display tank. That way water will only flow in one direction.

MarineGirl411 · #8 09/12/2006, 05:13 PM

well that sounds like a good idea. Would they have those at home depot? Hey vest I just got my typhoon. The di resin came wet. Let me know if yours does. I don't know why they had to do that. I am a little worried it isn't going to work now. It started to smell mildewy so I wiped out the canister it was in.

MarineGirl411 · #9 09/12/2006, 05:35 PM

Hey a question on the typhoon. I was wondering, if I want to use my tap water, is there something that will shut off the RO DI production? No one can seem to answer this question. What would I need to get for this?

northbay-reefer · #10 09/12/2006, 05:55 PM

Quote:

Originally posted by MarineGirl411
Hi,
Sorry again, I have another very important question. I will be running a sump and I am wondering how do I prevent a back siphon durning a power outage? Won't it flood my sump? Won't it ruin my pump? Please let me know. I'd really appreciate any response. I am starting plumbing this weekend. Thank you.

Marinegirl, make sure all of the water return lines is not too far down below the water line so that when you turn off all of your pumps and watch to make sure the water won't drain down down and flood your sump. Once you have that part dial in then you can do additional safeguard by drilling siphon break holes like some have sugested and also install a check valve. This will ensure your sump will never be overflowed.

The siphon break hole works well, but sometime it does get clogged up so don't count on it 100%, you will have to keep the siphon break holes clean. And the check valves sometime can get some sand in it and doesn't stop the water 100% of the time either. But the combination of these thing will work great.

xDave · #11 09/12/2006, 06:24 PM

This is what I use. The siphoning is also self restarting.

acwilson · #12 09/12/2006, 07:52 PM

yes, I believe you can get check valves at any HD or Lowe's.

MarineGirl411 · #13 09/13/2006, 06:38 AM

Dave,
I am kind of a well, airhead when it comes to things sometimes, if I do a siphon break like that, wouldn't water end up coming up the siphon break once the pump starts up again? I just want to make sure to be extra cautious about everything. I don't want to loose any inhabitants and also there is no way I could cause a flood without being in big doo doo. I live in an apartment. I have renters insurance of course, but I need to be safe. If I drilled the returns up closer to the surface of the aquarium, would it jeopardize the tanks strength at all? So far I am drilling 1 for the corner overflow then 2 for the closed loop. There will be T's with loc line in the back, with one loc line on each side of the tank headed towards the front then bent inwards to get the front of the tank. Then one on each sides of the back to get behind the rocks. Then with the closed loop there will also be a 3/4in Sea Swirl. Since it can only handle 850 GPH that is why I am using T's to direct other flow behind rocks and in front etc. How does this plan sound?

MarineGirl411 · #14 09/13/2006, 06:40 AM

Where would you guys direct the constant flow? This would be the flow coming in from the sump.

CoolUsername · #15 09/13/2006, 11:08 AM

MarineGirl411,

I agree with northbay-reefer, Drill your returns as high as you can manage. Then figure all the water above this is going to have to have a space for it in the sump when the power is off.

So if a siphon break hole clocks and if the checkvalve fails you wont have a flood.

In practice however it's still nice not to have so much drain ever power cycle.

Since you have configuration #2, drill a siphon break in the pluming at the highest point possible. And install the check valve as suggested.

Over the back returns (Config #3 above )don't have as much impact on your sump design.

WarrenG · #16 09/13/2006, 11:18 AM

For my returns via bulkheads I drilled a small hole in the top of the return (the part inside the tank) and put in a piece of the black airhose (comes with some powerheads) that goes to about a half inch below the surface. It's below the surface so air doesn't get sucked in like a venturi during normal operation, but high enough that it breaks the siphon on backflow before much water drains out.

On the drains, in the pipe outside the tank, the pipe goes UP to a point about a half inch below the normal waterline. If the return pump is off, water will only drain until the drain pipe is even with the water level in the tank.

pitbullpooch · #17 09/13/2006, 02:44 PM

Quote:

Originally posted by MarineGirl411
Dave,
I am kind of a well, airhead when it comes to things sometimes, if I do a siphon break like that, wouldn't water end up coming up the siphon break once the pump starts up again?

dont feal like an airhead over that because i was thinking the same thing. ive been around this hobby for a long time now and never seen anything like that done and i dont think it would work but hey you learn something new everyday so who knows. but i dont see it working and wouldnt even want to test it lol.

MarineGirl411 · #18 09/13/2006, 04:04 PM

So it's okay to drill the hole in the loc line?

devildij · #19 09/13/2006, 09:28 PM

use a real over flow in wich the outer box is watertightly divided in 2 parts so the intake utube is separed from the drain to the sump just make sure the divider isnt too high

pitbullpooch · #20 09/13/2006, 10:11 PM

Quote:

Originally posted by devildij
use a real over flow in wich the outer box is watertightly divided in 2 parts so the intake utube is separed from the drain to the sump just make sure the divider isnt too high

im lost on this one. is it just me???

seattlerob · #21 09/13/2006, 10:39 PM

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 · #22 09/14/2006, 04:31 AM

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 · #23 09/14/2006, 04:45 AM

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 · #24 09/14/2006, 08:03 AM

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 · #25 09/15/2006, 11:43 PM

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