Actually I think you got it turned around. First there must be enough water in the water trap to fill the over the glass and restart the siphon. Secondly, The higher the water is up in the water trap the less vacume is required suck that water up to reestablish the siphon. Inside the tank can be either the loop you have or just a single pipe. As long as the single pipe remains underwater the tank side can reestablish the siphon with the vacume. But with that system the power our level is determined by the vertical location of "F". So that has to be much higher then the design you posted. That design uses the inner loop to determine the power out water level. And that can be used even with "F" much higher.

As I stated the main design difference is simply the location of "F"

Or you crack the tank. Or the bulkhead leaks. etc etc etc.

the best you can do is to design and test it as much as possible.

power out to see of the sump floods.

power restart to see if normal operation returns.

failed overflow (siphon, blackage, etc etc) see if the display floods.

I have found out that there is usually a very narrow range where all those are met. Adding an automatic top off can screw that up also as water is added when the sump lowers. Which is fine for evaporation but can flood the display if it is from overflow failure. So I recommend some kind of drip system. Which can be a bear to adjust.

Have really enjoyed. Very enlightening. Thanks

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden

And here is a picture of my first test unit. If you study it closley you will notice that "F" from before is much higher and the riser tube is just shorter. And I also show the drain to the sump and don't use the inside loop surface skimmer.

this picture is a mag 7 pumping against a 4' head.



Hidden behind the hob part is the in tank drain which is just a straight pvc pipe going down about 2/3 the way into the tank.

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden

Th e water will stop at B will not go over D next to F

Got that.

under power out it would seem the outside the tank part would drain down to "F". And if the over the tank part has no air leaks then it stays primed. So normal operation would return on power resume.

but if air does accumulate or if "G" has an air leak then the over the tank part breaks siphon. The in tank loop is at the top of "B" but the external loop is down to "F". So to restart the siphon the water in the external trap at "F" must be sucked up the pvc pipe. My fear is that there is not enough water trapped to restart the siphon.

In order to insure there is enough water traped to restart the siphon you could just raise the position of "F" to just below the top of "B". That way "F" traps much more water at a higher level. Helping insure the siphon is restarted.

To exaggerate my point consider placing the "F" near a sump in the basement. Say 15' below the tank. There would be a much greater cavitation potential. Greater check valve/aqua lifter failure. And not enough water trapped to reestablish the siphon. All of which is avoided by raising "F" to just below the top of "B"

just my .02

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden

There is no reason to do anything to this. The instructions I posted for it works 100%. You know what they say if its not broke Dont fix it.
Remember what I said it been on my reef tank for 4 years. Hasn't lost siphon once in that time.

There is no reason to do anything to this. The instructions I posted for it works 100%. You know what they say if its not broke Dont fix it.

Attached Images

overflow.jpg (38.1 KB, 11 views)

Thank you very much

It has been an interesting discussion.



my .02

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden

Have you has a chance to do a shut down/ start up test on your design yet? I'm interested to see the outcome.
I haven't had a chance to pass the design along yet, but I will try to consult some peopl about it when I get home from work.
If you can, PM me the design drawing (w/o the AF logo if possible)

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why buy, when you can DIY

Hopefully you meant me. Yes I could pass along some pictures and drawings.

Not only have I tested this out but actually did a demo for the a local club meeting. In that demo I started out with filling the sump, showing how the return pump could remotely fill that tank, establishing the siphon, and adjusting the system to prevent flooding.

In the testing and demo's I plug the overflow as well as remove the suction lines on the over the tank part to allow air to enter and break siphon. I also demo the air pump pumping air into the drain to show the venturi suction lines sucking the air out.

And of course the normal power out power return conditions.

I am at work now but will try pming/emailing pictures/drawings at home tonight.


my .02

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden

Very nice! Looks like you got all the test taken care of. That's awesome.

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why buy, when you can DIY

Here is a link to my photobucket page. It has the above plus a revb (in album refb LOL) and a rev c which is similiar to the drawing I started this thread with. Only in these pictures I used straight tees instead of the curved sanitary tees which I now recommend.

Click on those albumns to see those designs.

also is a test setup in my messy garadge

pvcoverflow pictures by beaslebob - Photobucket

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden

Beautiful. I've been pricing overflow boxes and for the price of a good overflow, you could easily build two of these contraptions to work in tandem and should fail over if one doesn't start properly after power fail.

Actually. Given the price of PVC, you could easily make quite a few overflows. 10' lengths of PVC only cost a couple of dollars. (I believe 10' @ 1" is around $3)

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why buy, when you can DIY

Exactly. I've nearly worked up the bravery to build my own sump & refugium. If some PVC and strainer will replace an $80 part It would certainly help my case. I'm going to pick up some 1/2" PVC on my way home from work and experiment tonight with a bucket.

The thing is I don't want to drill my aquarium and I don't want a wet floor.

For what size tank?
1/2" is too small for most applications.

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why buy, when you can DIY

I even tried (without any success) to heat up pvc filled with sand to form an p or s trap. Found it easier to just buy the elbows and tee's.

Let us know how your testing works.

Perhaps you can come up with a rev d to "my" design.


FWIW the sanitary tee's in my drawing could be replaced with just regular tee's for testing.

Also 1/2" will probably not allow much flow. But it will be nice and quiet as the pipe will be full of water. Larger diameters do allow more flow. But unless the overflow is fairly near it's maximum flow rate there will be some air in the pipe which will cause a small smount of "flow" sound as the over water hits an elbow on it's way to the sump.

I also used a 10g for my tank. You might want to get a couple of plastic storage containers to simulate a sump and tank.



my .02

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden

Yea but you can buy contractor packs of elbows (and maybe even tees) at 10 for $2 here. sounds like a good plan to just test it out and see if it works.

but I do agree that an over flow with two 1" hob siphon parts would be more useful. In my last testing I used 1" (or1/4") hob parts (2 of them) to a center 2" up then down part. The two overflows were much easier to mount on the tank. It also easily drained a mag 7 pump pumping against a 4" head.

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden

What tank size? This will be a 5 gallon bucket of water draining into a sink. I have no intention of using this for an aquarium, but only a proof-of-concept. I purchased all the stuff for under $5.

If anything really awesome happens, like I actually get it to work, I'll make a video and put it on youtube.

I'll even try to get video of my wife giving me that "what the hell are you doing?" look.

The first try, I just used 6 elbows, no Ts, no pvc cement, just plugged everything in and it worked.

Will go back in about 30 minutes and pour more water in my bucket to see if the siphon held. It wouldn't surprising me if I have an air leak, though, having not even cemented the pvc.

It's crude at this point, but it works.

Excellent. got pictures?

FWIW I set up my first pvc overflow and it worked just fine. Of course that was after 1 year or two of running a sump with the standard dual box overflow.

I showed it to my wife and she was so impressed that she said I should patent it. So I checked and the s (or p) trap was first patented in 1850 or so.

Look at your toilet bowl from the side. You will see why you can slowly pour water in the bowl and the level in the bowl reamains relatively constant as the water goes down the drain. So basically you are turning you tank into a toilet bowl.

my .02

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden

Oh yea. Did you have problems first "priming" the siphon and water trap?

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden