will this overflow work

  • We are currently upgrading MFK. thanks! -neo
Short answer is no.
Expanded answer is, maybe, but only with a check valve on your drain line.
Not sure why you want your skimmer to be as tall as it is, since it does nothing to help keep water in the drain for restarting should your pump stop running.
Maybe just me, but no way would I pin my hopes for dry floors on a check valve alone.
Without a valve on your drain, stop the pump, and most all the water will flow through your pump and leave you with a pipe full of air.
There are vary few pumps that are self priming in the aquarium world.
There are a large number of proven designs on this site, but I don`t think I could add this one to the list.
The last really cool design is this one.
http://www.monsterfishkeepers.com/forums/showthread.php?311243-DIY-Overflow-Ver-9999
 
the question was if this idea would work...well yes it will work. the 1" pvc will pull all the water out of the larger pvc pipe no problem. but as the others have stated the siphon will break every time. now if u don't mind restarting it everytime u shut the pump off then it will be fine, but most people would prefer not to. there are loads of designs on here that will work better imo
 
Yes, that should work. The siphon should stop when the water level in the overflow reaches the level of the T on the outside of the tank. When the water level in the overflow goes back above the T the siphon should start on its own. To make your picture a bit more accurate raise the water level in the overflow (from half way up the overflow) up to the level of the T. This would be the static level of the water inside the overflow. Any water in the overflow that is above this level will be pressure pushing the water through the piping.

I.E. - The distance from the T to the water level in the overflow will determine the amount of drop in the siphon... and the amount of water pressure in the siphon... hence the flow rate. In other words, the lower the T is outside the tank the greater the potential flow will be.
 
so what if i got rid of the last elbow and put the T in its place

It won't work! The U keeps the water that restarts the siphon after a power failure in the pipe. Without it all the water will drain out and it wont automatically restart. You will need a bit of distance from the top wall on the bottom of the U to the bottom of the T. When water is cut off the inertia of the water will cause some of the water in the pipe to continue flowing and spill out through the T before the water comes to a static state. To little distance between the U and the T and the siphon will break.

When I built my overflow pipe I was able to test it with the parts just press fit together allowing me to make a couple of tweaks before committing to the design with cement. Be careful about trying this though... one wrong bump and you will have a lot of water on the floor before you can stop the flow. The bottom of my U is at the bottom of my tank. My T is about 6 inches up from the U. The valve you have drawn comes in very handy!

I have a 110g tank and the 1" pipe is just barely enough flow to keep up with my bigger pump. I should have gone with 1.25" pipe.
 
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