# DIY overflow not working right, suggestions?



## xmas_one (Feb 5, 2010)

1" is kinda small. You either have a leak, or you need to bump it up to 1.5".


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## VAtanks (Feb 1, 2013)

You may be sucking air around the check valve tube, or the check valve is bad so it looses the prime.


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## Hoppy (Dec 24, 2005)

When I used one of those I found that tiny air bubbles would collect in the outside "U" (upside down). As enough of those collected there they would finally be one big bubble big enough to break the siphon. I then had to restart it by connecting a water hose to the drain line outdoors, plugging the vertical vent pipe, then running a heavy flow of water to fill the whole thing with water again. Turn off the water, take the cap off the vertical drain, and it would start siphoning again. This happened about once a year. Mine was made of 1/2" CPVC pipe.

I believe this works much better if the outside "U" (upside down) is at the same height as the opening in the vertical drain pipe in the tank, or just slightly above it. Otherwise you can lose the siphon over the edge of the tank when the flow stops.


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## Brich999 (Mar 17, 2013)

My aqua lifter is prone to clogging unless u use thenprefilter which I broke. Keep an eye on the outflow of the aqua lifter and make sure it's working properly or itnwill keep losing siphon


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## SlammedDC2 (Jun 4, 2011)

xmas_one said:


> 1" is kinda small. You either have a leak, or you need to bump it up to 1.5".


I have no leak, and the size is perfect for the flow I want. It ran for a year with zero problems.



VAtanks said:


> You may be sucking air around the check valve tube, or the check valve is bad so it looses the prime.


 I never even thought about the check valve, I'll take a look.
[
QUOTE=Hoppy;2858114]When I used one of those I found that tiny air bubbles would collect in the outside "U" (upside down). As enough of those collected there they would finally be one big bubble big enough to break the siphon. I then had to restart it by connecting a water hose to the drain line outdoors, plugging the vertical vent pipe, then running a heavy flow of water to fill the whole thing with water again. Turn off the water, take the cap off the vertical drain, and it would start siphoning again. This happened about once a year. Mine was made of 1/2" CPVC pipe.

I believe this works much better if the outside "U" (upside down) is at the same height as the opening in the vertical drain pipe in the tank, or just slightly above it. Otherwise you can lose the siphon over the edge of the tank when the flow stops.[/QUOTE]
I'll check to see if that helps as well.



Brich999 said:


> My aqua lifter is prone to clogging unless u use thenprefilter which I broke. Keep an eye on the outflow of the aqua lifter and make sure it's working properly or itnwill keep losing siphon


I don't have a prefilter, nor did I know they had them. So far they still suck water great, but for some reason it doesn't seem to have the strength to reprime the 55g, my 125 has been up and running longer and never has a problem with the prime when I shut the power down. I will take a look at it either way, what is the best way to clean the aqua lifter?


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## HD Blazingwolf (May 12, 2011)

replace the diaphragm in it  its cheap and it adds a lot of umph back to one
alsoi stick a toothpick through the ends of any fitting in mine weekly. small snails like to get stuck.


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## jamesyu (Feb 13, 2012)

I wish someone can give me a tutorial on this because I built one when I had a marine aquarium and it NEVER worked. well I can't say it never worked but it was loud as HELL!

so much gurglling, and the water level varied so much that I was afraid to leave it over night since it might flood. I could never get this to work out. anyone know how, please let me know.

mine was a 10 gal .75" into a 10 gallon sump. PVC cemented and added a aqualifter which was loud as hell as well.


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## HD Blazingwolf (May 12, 2011)

jamesyu said:


> I wish someone can give me a tutorial on this because I built one when I had a marine aquarium and it NEVER worked. well I can't say it never worked but it was loud as HELL!
> 
> so much gurglling, and the water level varied so much that I was afraid to leave it over night since it might flood. I could never get this to work out. anyone know how, please let me know.
> 
> mine was a 10 gal .75" into a 10 gallon sump. PVC cemented and added a aqualifter which was loud as hell as well.


its about flow dnamics, and pressure equalization
drains suck in air. having enough room in the drain and a place for it to go make ALL the difference in the world

300 gph is max for a 3/4 inch pvc in a striaght run. bends and strainers/ adapters reduce this. there also needs to be a place where air can be either sucked in or vented out
smaller strainers sometimes come with this drilled on top where u can stick some rigid tubing down in it to find the sweet spot


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## SlammedDC2 (Jun 4, 2011)

I'll try the toothpick on it, thanks guys.


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## scotty b (Oct 23, 2012)

would it work to put a toms aqualifter out put int the hole where the airline goes?


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## Hoppy (Dec 24, 2005)

This is how I made my overflow. Note the water line. When the water stops flowing in the inlet to the overflow, there is still a siphon being maintained. But if air bubbles build up in the high point over the top of the tank it stops the siphon.


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