Originally Posted by SocalNano24
http:///forum/post/3275430
your PVC overflow looks great, I've been looking at the threads on how to make one of these myself, in lieu of a core job for when I finally get around to my 40 gallon upgrade. Can you explain what you have on the end of the clear airhose? Is that a one way valve essentially, like does it release air or suck air?
Also can you explain how it stops syphoning if the power goes out? In order for it to stop syphoning does the water merely drop below the top of the intake pipes? In which case those pipes would need to be about 1/2" from the top of your water in a full tank scenario?
Btw it looks pretty nice; I'm tempted to go get myself some PVC now and tinker
I would go for it.
Here was my first attempt which help explains how it works plus there are several other designs on that photo page
the answer is that the water overflows at the horizontal pipe 3. the drain above 4 is open to the air. The running water level in the tank is at 3. The picture shows a mag 5 pumping against a 4-5' head.
Under power out the tank drains to the bottom of 3 so water is trapped in 3 and the hob siphon. Actually 2 has the highly technical term of a water trap.
Then when power returns you still have sihpon so the water rises in the tank and 3 and starts draining down 4.
You can do several other designs which make thing easier to mount on the tank but this simple design I hopes helps explain things.
Hey for $20 of pvc it's worth a try.
my .02
