Plumbing/Siphon/Water Disaster Avoidance Advice

[Der_Iron_Chef]

I'm working on the group home aquarium set-up (yeah!), and I want to plumb a return line (from the sump) that enters near the bottom of the aquarium. Obviously, were the power to go out, it could create a siphon and empty almost the entire contents of the tank out into the sump, onto the floor, etc.

I'm hoping to avoid this!

So, if I had a return line placed like so:
http://x6c.xanga.com/847c330b07333161192759/w121335331.jpg

Could I frankenstein it like this....and would it prevent a siphon?
http://xa3.xanga.com/cf7c010b07330161192764/w121335336.jpg

Thanks in advance :wink:

[untamed]

No. That design will siphon equally well.

Your best bet is a check valve...or bring the return in over the top of the tank instead of straight in the bottom. If you did that, you could also incorporate a siphon break.

[Delphinus]

If you look up "Carlson surge device" you'll see that they have a similar design in the surge tank. The tank fills to the top of the U-tube and then siphons the tank empty to the bottom of the U-tube. :)

Anyhow, personally I generally caution against check valves. Without due maintenance/cleaning the seal can fail (the technical reason is that goo grows on the insides of pipes.) Plus they put a bit of backpressure on a pump slowing the flow some.

I second untamed's suggestion for over the top. Just drill a wee little hole at the water surface and this will introduce air into the pipe when the pump is shut off, thus breaking the siphon. The only thing is you have to make it a chore to clean the hole out every few weeks to ensure it's not clogging on you. At least with my tanks this hole seems to be the favourite spot for valonia, I guess I should be glad that it doesn't grow everywhere else but I'll get a 2mm valonia in the hole and it seals it up perfectly. :neutral: So I just take a nail and pop it when I see it there.

[Der_Iron_Chef]

Good call. I didn't *think* it would work, but thought I'd ask anyway. Also, I wanted to show off my mad skillz in Microsoft Paint.

[GMGQ]

If you do wanna go ghetto, why not drill a hole at the top of the pipe, stick in a piece of airline tubing, seal around it with silicone, and feed it over and into the tank:

http://auphanonline.com:8080/gallery/images/uploads/1/l_071205172441_432_1.jpg

Water will exit from it into the tank when in normal operation. When the return pump stops, air will get sucked into the airline tubing, and break the siphon.

Only problem is that it may get clogged if there is debris being shot up by the return pump, and it may clog after a while... Or you could use some sort of tubing with a wider diameter.

[Chin_Lee]

i would drill some holes at the top of the U as it come over the top just around where the water line will be. This will introduce air into the tube therefore breaking the suction of the siphon. But due diligence to keep those holes open is needed - such as removing coraline algae growth. I would drill 2-3 holes because moving snails could plug up the holes just when it "least expect" it. Likelihood a snail is over one hole is slim but possible, over two holes simultaneously very unlikely, but over three holes...... the reef gods must be angry and somebody's gonna get hurt...... real bad.

[digital-audiophile]

Is the tank already drilled, is this why you are looking at it this way?

[Der_Iron_Chef]

Yeah, I actually drilled it for a closed loop, and then changed my mind. Doh! So now I'm just trying to make the most of it.

[mark]

Might not help your livestock but a really really big sump would keep the water off the floor :wink: .

Could also internally to the tank raise the height of the return nozzle so any water drained back would be manageable.

[kwirky]

what about attaching an airline as a siphone break (or two for safety) and putting a check valve on the airline so the air only flows one direction. fixes the spray from pump operation...

[MikeP]

You drilled it yourself? Why not just plug that hole and drill one where you want? Or plug that one and run the return line over the glass?

Just a thought :)