preventing back siphon

[Capt_Cully]

Looking for a creative solution to preventing back siphon of return line. I'm not sure I want to rely on a gate valve. Planning on having 2 penductors on the end of the return. They will need to be 2 or 3 inches under the surface. Multiply that by a 4x3 foot footprint and that's a lot of volume for a sump to account for.

Any ideas???

 

[toddmh]

I've heard of people drilling a hole in their return line just under the surface,so when the water drops below that point siphon breaks..

But I'm not sure how large a hole would be needed and if the hole its self would be problematic for the return

 

[tropills]

small hole in the return line just below the water surface works on mine..

 

[byrdman81]

Drilling a hole in return works great used it on an old 75. Just make sure to drill two holes instead of one. Reason being in case a snail is over top of the one hole when power goes out you wont break siphon. The reality of that is very slim but its better to be safe than sorry. Your just looking for somthing to draw in air if power shuts down. A check valve wouldnt hurt either for extra piece of mind.

 

[sedorusc]

I have a check valve on mine and works great

 

[Tonynlo]

+1 to drilling a hole. I have 2 x 1/4" holes in my return. Drilling tip... drill them at the bottom or at least on the side pointing down. I wasn't thinking on my first attempt and drilled the top. When I turned my pump on water was forced through the holes and soaked my light. Also, if you have enough space, make your sump large enough to hold all of the water that would siphon out of your tank.

 

[Conesus_Kid]

Here's another reminder to make sure the hole(s) you drill are angled downward. No need to spray the inside of your nice new canopy.

 

[ggdowski]

I've used both. It only takes the tiniest of holes on the top of the return line. On the last system I used, it was literally almost the smallest hole I could drill. Last week I finally put together the wet/dry on my freshwater tank and I used a check valve. The check valve adds some impedance but it adds considerable piece of mind.

The hole method does work just fine.

 

[naprestsleep]

I added a hole to the return on my refug so it would break the siphon before reaching the loc line nozzle. Works great but I would also emphasis making sure its pointing down and small, maybe a few tiny ones. Mine a little big and points up a little, causing water splashing.

 

[Tonynlo]

If you do not want to drill into your actual return, you can attach a piece of PVC coupling somewhere to your return.

 

[Capt_Cully]

I can drill holes easily enough. My concern is that it might reduce the pressure going through the plumbing, rendering the penductors less effective. If you guys think the difference is nominal, I'll just go for it.

Thanks everyone!

Oh and I'll incorporate a check valve too :thumbsup:

 

[Dave VG]

You don't need a big hole I used an 1/4" drill bit to do mine 2" under the water line. Be shure to do what Scott said and make shure it is angled down tho. Allso check it once in a while to be be shure it dosen't get blocked up.

 

[Conesus_Kid]

Either way, plan on the siphon holes AND check valve to fail simultaneously at the worst possible time. Imagine that you're out of town, there's a power outage, and your check valve and siphon breaks fail. Oh, but your wife is home.

How much water will overflow the sump? Can you seal off the stand so that any water that does overflow the sump will stay off the floor?

Redundancy is good (check valve + siphon break holes), but planning for all of your failsafes to fail is even better.

Just trying to help you avoid any potential divorces or murders...

 

[coralfish]

Either way, plan on the siphon holes AND check valve to fail simultaneously at the worst possible time. Imagine that you're out of town, there's a power outage, and your check valve and siphon breaks fail. Oh, but your wife is home.

Yea tell me about it!...my tank can run flawlessly for months while I'm home, but while I'm on my way out of town....BAM! something goes wrong with something. And try to explain to your wife; looking at the back of the tank, follow the white pipe down to where it goes into the tank under the cabniet (she actually told me "There is no tank under the cabniet") OM, someone call the cops cause it was there when I left! And where is the water from the main tank going if it ain't there!

 

[Capt_Cully]

Either way, plan on the siphon holes AND check valve to fail simultaneously at the worst possible time. Imagine that you're out of town, there's a power outage, and your check valve and siphon breaks fail. Oh, but your wife is home.

How much water will overflow the sump? Can you seal off the stand so that any water that does overflow the sump will stay off the floor?

Redundancy is good (check valve + siphon break holes), but planning for all of your failsafes to fail is even better.

Just trying to help you avoid any potential divorces or murders...

Here's the deal with redundancy. The sump will have a failsafe overflow drain, hooked to the household plumbing. It will also be in service during water changes. In the event of a power failure, should check valve AND siphon break fail, there wont be a flood.

BUT should all that happen, and power kicks back on, ATO will refill the missing volume. This would in turn, dilute the tank and drop SG....UNNOTICED.

That wont get me killed, but it wont be the best situation for my livestock.

 

[Gary Majchrzak]

I used to run with a check valve (for about 9 years).

They're no good. Junk. Don't do it. Plus- they're an added maintenance chore (they get gunked up) and restrict water flow. Don't do it.

Search up "the hammer effect" of a check valve. Don't do it.

I now run multiple siphon breaks on my water returns. As an added bonus each siphon break creates an area of water movement. The loss of pressure on each penducter is minimal.

 

[pascal32]

another option is to put a locline T on with a lockline valve and nozzle near the surface. when the volume drops this line will pull air. This is how I have all my tanks (without the valve - added so you can pressurize the penductors.)

 

[Capt_Cully]

another option is to put a locline T on with a lockline valve and nozzle near the surface. when the volume drops this line will pull air. This is how I have all my tanks (without the valve - added so you can pressurize the penductors.)

Yeah Pascal, that was one of my thoughts as well. I have a ton of Loc-line left over from my last tank. I thought perhaps T off one arm. One limb to Penductor, one with Loc-line near the surface, with one of these:

http://www.bulkreefsupply.com/store/inline-ball-valve-for-3-4-loc-line-modular-hose.html

That way I could regulate how much comes out and how much gets to the penductor. I think I'd have to keep an eye on salt creep, but if it was just under the surface, that might keep it in check.

I kept my old tanks this way as well.

Bottom line, redundancy is our friend.

Thanks for the varied points of view guys. Just what I was looking for!

Mark