Looking to silence DYI overflow siphon

[Morrisons]

Hello,

We have a DIY overflow siphon that seems to work great. Trouble is it makes a loud sucking noise.

I've been experimenting with ways to make it quieter such as the Hofer Gurgle Buster. However our siphon is pointing down and all of the Gurgle Buster designs I've found are pointing up. It's sort of like we need a reverse-Gurgle Buster...?

Anyway, I've got some ideas about using a float to control an air intake above the water level so-as to remove the gurgling sound, but still increase the siphon if the water gets too low.

Attached are some pictures of what I have now.

Has anyone designed or built a Gurgle Buster that would work with our style of Siphon?

Thanks in advance. :)

-Mike

[RocketEngineer]

I have never seen one like that before and I built a functioning PVC overflow before. The way you have it set up, should the pump stop the entire thing drains and will fail to restart. To me that is a very big problem and you need to address that first. There should be a pipe inside the tank going down, then two elbows to have the inlet facing up, not down. Second, where the tee is on the outside of the tank, that shouldn't be run back into the tank but instead be open to the air.

These are not high flow devices. Attempting to push a lot of water through them is asking for trouble.

[Morrisons]

Hmm, it does seem to work however. Maybe I'm missing something, but below are the details.

We tested it extensively in the garage before moving it into the house. If the water level drops below the short down-facing pipe the siphoning stops, the longer pipe hold the water however, so when it rises again, the siphon restarts. Also we tested killing the power and let everything settle. No issues.

Note, it doesn't restart immediately, the water level gets about a half inch above the bottom of the short pipe before it starts siphoning again at full strength. Then pulls the water level back down.

Another note is that the tee where the two pipes meet on the outside of the tank then routes down below our tank to the sump.

We currently have a 500gph pump in the sump back to the tank and the siphon has no trouble exceeding it.

FWIW, in almost two months we've only had two overflows (that we caught with our alarm). One was when we had a small mesh on the short intake and it was plugged with seaweed (we now have a larger mesh). The second time was when a snail somehow climbed onto the short intake and blocked enough of the flow that the siphon couldn't keep up with the pump.

-Mike (not a rocket engineer, but I do build and launch a lot of them... :)

[RocketEngineer]

Do you have a website that you got this design from?

What you want is this:
http://i2.photobucket.com/albums/y40/kbmdale/Plans/overflow2s.jpg

Notice that when the pump stops pushing water into the display, the two upturned tubes, one inside and one outside the tank, trap water in the pipe that goes over the glass. Also, where the water comes out is open to the air so that it prevents the water dropping into the sump from draining the rest out of the pipes.

[OnceTrueFalseBr]

Do you have a website that you got this design from?

What you want is this:
http://i2.photobucket.com/albums/y40/kbmdale/Plans/overflow2s.jpg

Notice that when the pump stops pushing water into the display, the two upturned tubes, one inside and one outside the tank, trap water in the pipe that goes over the glass. Also, where the water comes out is open to the air so that it prevents the water dropping into the sump from draining the rest out of the pipes.

is the overflow submerged pointing down or up in the slotted cup?

[Morrisons]

Ah you are correct. Thanks!

Previously when we tested it I guess we didn't wait long enough. If I let the water drop below the short pipe and then wait long enough too much water drains out and then it won't restart. It recovers from short disconnects, but not after a minute or so.

Guess, it's time for another trip to Home Depot...

FYI, I did learn about this design from a post somewhere, but I can't seem to find it tonight.

-MM

[RocketEngineer]

is the overflow submerged pointing down or up in the slotted cup?

The cup in this picture is glued to the top of the inlet pipe which is pointed up.

The way this works is as follows:
1) The return pump comes on and beings pushing water into the display where the water level rises until it goes over the lip of the cup
2) The water enters the overflow plumbing and begins to raise the water level in the tank side of the u-tube which is totally full of water.
3) Because the u-tube acts as a siphon, it maintains the same water height outside of the tank as it has on the inside of the tank. With water coming in one side, the siphon in the u-tube transfers the extra water to the outside of the tank in an attempt to keep the water level on both sides of the glass the same.
4) As the water outside of the tank rises within the overflow, some of it begins to drain out the side of the tee. In doing so the levels never reach a static equilibrium. Instead, you get the flow entering the overflow equals the flow out the drain pipe.

Here is an image showing what I'm talking about.
http://www.melevsreef.com/plumbing/refugium.gif

Any of the HOB overflows that you can buy and the PVC version all work on the same principles. The issue with the PVC version is they typically have very limited surface skimming and pushing too much water through them is a challenge. While they work, the better solution is a purchased version. If you have the chance, the best option is still a drilled tank as it only needs gravity to work, no siphon tube that can fail.

Hope that all makes sense.

[Morrisons]

After doing more research. I was considering getting a new C-Siphon overflow box but even they recommend using an "Aqua-Lifter Dosing Pump" with it.

Realistically, if I just had the dosing pump and added it to the one-way valve on the top of the short pipe, then our siphon would automatically restart (that's how we start it ourselves, by sucking the air out of that short tube).

Any thoughts on that approach?

-Mike

[RocketEngineer]

I would build a new PVC one at the minimum which is more in line with what is shown above. After that, using a dosing pump on the check valve isn't a bad practice.

A commercially produced HOB overflow box with a u-tube typically doesn't need a pump to keep it primed especially if run at the correct flow rate. The u-tube they employ is a much smoother curve and because of this and the high flow rate through it, air does not get trapped at the top and cause problems.