Question about U tube type Overflows

If he did it as I used to do it before I learned about a standpipe (I made my first overflow box), he most likely filled the tank side, used a glass of water, and poured it into the external side, and sucked through aquarium tubing threaded into the U-Tube and started the siphon before the water level in the external box went too low. Once started, the siphon will hold forever. Until, of course, a power outage.

 

Oh what a pain that would be! I used to kind of start mine that way, but it wasn't a beat-the-clock scenario. Each side would just have water in it, again because of the standpipe, and then I'd suck the air through the same way you described. But now I submerge my tube, cover each side with saran wrap and it clings beautifully to the tube. Simply turn it over and remove the cellophane and viola!

 

That's clever! I'm so glad I got my drilled 90.

 

Do it exactly the way u said with the airline tubing

 

It sounds like the issue has been identified. All you need to do is extend the standpipe so that when the pump is off the water in the external part of the overflow never drops below the bottom of the U tube.

Just get a piece of PVC that will extend the standpipe an inch or two higher. Just make sure the top of the standpipe isnt higher than the bottom of the teeth on the skimmer box inside your tank or it may not flow as well.

 

I'm familiar with that problem. I had bubbles too, but never to the point where the U-Tube lost its flow. I remedied that problem by installing a ball valve on the return pump's output back to the tank. This slowed down the whole system to the point where the problem stopped.

The bubbles semed to happen because of a sizable gap between the tank water level and the water level in the internal O.F. box. There was this waterfall phenomenon that caused the bubbles. Apparently the O.F. box inside the tank was evacuating faster than the return pump could fill it. You'd think that dialing back the return would exascerbate the problem, but it didn't.

Slowing the return pump brought the water level in the tank and the internal O.F. box closer to one another. That was that.

There's a lot of trial and error in getting our systems to work as we desire. Once we get it, though; we don't have to incessantly fiddle around.

 

I have no problem with it. Hopefully Luna will be as gracious. He's the pic police 'round these here parts.

 

Maybe the bubble problem is from the internal overflow being to low and causing the water to drop in and cause bubbles and getting sucked up the tube. I keep my internal overflow almost full, just so the water can fall through the teeth and touch water with no bubbles.

 

Why not also add a battery backup / UPS, so you're still operating, when the power drops out for the short term? It'll keep the return going.

...had to post, eventually.