the VanSiphon

They were right next to the domed caps in my Lowes, PVC isle. They look like they would be used to cap some PVC if you were storing something in it. Just like the post office tubes with the caps on each end.

I will say though that they don't do really well with PVC glue, I had to go back over them with some super glue and silicone just to be sure.

Mine for the most part sits on top of my stand:

 

Scadsobees,

I'm not trying to hijack your thread, I like your design.

I'd like to show mine, only uses less than 2" behind the tank also.

That nice for smaller tanks.

I have a similar DIY 'intank overflow' and DIY HOB overflow that pushes about 900GPH.- Thats about what my Marineland 5500 puts out a a 3.75Ft head.

Like the OP, I needed more flow, and I wanted more surface skimming linear length.

I also had to have something that: 1. Would not flood my sump in a power out, and
2. NEVER loose siphon, especailly in a power out!

So I researched and built what I feel is the best alternative to a drilled or RR tank while having max. flow and large surface skimming linear area.

The design of the OP, using a 2" 'intank' pipe, gets 6.28" of skimming area.
My design, (in a 125g), has 21.195 (3.14 x d).

First pic, is my mod that put a 6" pipe, on my existing 4" overflow.
Thats why the top is white, while the bottom section was already painted.

Second pic, a top view. This is what skims the surface and falls into the pipe.
Over 21" in circumference.

Third pic, The final painted product of my 'intank overflow'.

Fourth pic, the top of the it with the DIY HOB overflow that goes to my sump.
The sump is DIY, 50g rubbermaid-but thats another thread!
The water level is down some in this pic, 'cause I'm putting it in and it wasn't running yet.
You can see the 6" 'intank overflow', and the 1.5" HOB overflow, with the vent pipe and the cap for noise suppression, has a 1/4" hole for the vent to maintain the siphon in a power out.
You can also see the cheapo WalMart one way air valve the air line to 'start' the siphon once you get water in the intank overflow, and in the bottom loop of my HOB overflow.

Fifth pic is my '21" linear length of a circulat cone of water' feeding the sump and return at 900gph.

I'll post some more as I reached the 5pic limit here, and don't know how to add them to the body of the post.

 

A few more pics of my set up.

Easy to build, hack saw, PVC cement, cheap $.

1. Side shot, my tank was 6" away from wall for my commercial overflow box, that was NOT enough flow for me, so I built the third version you see here.
Works awesome, HIGH flow, NEVER loses siphon. It's not really noticeable in my large family room where my DT is.

2. The bottom with my noise suppresion 'reverse durso', has a cap on top with a 1/4" hole drilled. Really helps quiet 900gph flow down.

3. Pick of the HOB portion, It's 1&1/2" thru out.

** 4. THIS IS NOT MY DRAWING! THE SIZES SHOWN ARE NOT MINE!
MINES BIGGER! (I know there's at least one of you saying 'that's what she said!)
This is where I got the billiant idea from another thread.
Except that mine has a 90 bend on top of the vent tube, to 'hang' it on the tank with.
I aslo do not have the 90 bend of the inside ar the bottom the 'intank overflow' tube.
I also found it much better flow without the notched teeth, which severly cut down the total linear skimming linear area.

Here is my lastest DT vid, showing the overflow and sump near the end of the 3 min. vid.
http://www.youtube.com/watch?v=pVQf7rC8VF4

 

Scadsobees,
You posted in the OP :The only problem I've had was when I was on vacation and my topoff failed, my pump was blowing bubbles into the tank and somehow over the course of a day or two it lost siphon. But that was the only time.

If the top off failed in the sump, how would the overflow loose siphon?
Wouldn't it just quit b/c the level in the tank fell slightly below the level of the intank overflow tube?- yet keep it's siphon b/c both ends were still underwater?
Do you have a pump on the line on the upper loop like an aqualifter? If you do, I could see how it would fail if the intank overflow quit feeding water, the upper loop siphon bleed off/siphon starter tube would suck out the water in the first loop going over the tank side-which would stop the siphon- right?
My design could even potentially do this if it was not a power out.
In a power out, the power to the aqualifter is also out, so it won't empty the upper loop which would then loose the siphon.

It must have been a long vacation- good for you, or there is not much room for error on your set up as in extra sump volume.

I've turned off the aqualifter on my design for days at a time- no siphon loss. the flow is too great thru it and what little bubbles do get down into the overflow, it never stops it.
I think I'll do it again, b/c if the aqualifter is always on the siphon purge line, and the output stops putting water in the tank w/o a power out, the aqualifter would pull the water out of the loop and stop the siphon. That's OK too 'cause I'd notice it before I got the output working again.
This has never happened, Im just trying to create scenarios where it might fail.

 

Scadsobees,

Mine is up and running, filled the tank with water and LR tonight. I will get some pics of it all tomorrow. Have a couple leaks to fix, nothing major. Just need to tune it in a little, making lots of bubbles right now.

I will also be adding an emergency return pump kill switch, just in case I loose siphon for some odd reason.

Thanks for the design!

 

I cannot get the bubbles down to a minimum, any advice? My return is running at 100%

 

Stercus, where are you getting the bubbles? In the tank from the return?

 

Todd, I have no idea. Both ends stay in the water. That was my only problem. It was only a day that it was out, the temps were high so evaporation high, and the return was blowing bubbles for that day, I have no idea why it lost siphon...unless I've got a tiny air leak on the top of my siphon so it lost prime over that day or two. Thats a possibility.

I've had no other problems with the siphon. I turn pumps off all the time and back on during water changes, and never have run an aqualifter or had to reprime the siphon.

You have a nice design too, same principles. You can push a lot more water through with the 2" pipes versus the 3/4" pipes.

 

Getting bubbles in the sump from the drain. I might try and build a small box out of acrylic to hold my carbon and some blue filter media to try and cut them down, but would love other suggestions. I know I will not be able to completely get rid of them...

Siphon is working great so far, although I did raise it up off of my cabinet to get the level in the bulkhead up some...it was incredibly loud falling all the way to the bottom

 

Do you have the output terminating underwater in the sump? I've found that it is best to have output fall into the sump versus terminate underwater in the sump.