Question about U tube type Overflows

The problem is that yes it does break the siphon and I had 10 gallons of saltwater on my carpet yesterday when I got home from work.

 

Is it DIY or brand name, if so which brand? I have a Lifereef on my 34 Gal, I shut my pump down quite often as well as a couple of power outages and I have never lost syphon.

 

Then you don't have it setup properly. Can you get us a pic?

 

any way to snap a pic of how you have it set up it may help everyone understand a little better.. I`ve had mine on and off plenty of times with no siphon loss (knock on wood lol)..as long as the tube is submerged on both sides of the over flow and does not go below on one side you should hold a siphon...

 

Brandon1023 knows of what he speaks. A properly set up U-Tube driven overflow will not break siphon. If it does, it's because it's not set up correctly, or you're missing a standpipe on the outside of the tank side.

You'll have to click on the drawing to see it. Excuse the kindergarten flavor, but I think it makes the point. When you have a power outage, on the tank side the water level doesn't go below the teeth on the top of the box. The u-tube should be near the bottom of this side--no siphon break. No issue.

On the outside the tank side, I'm guessing you're lacking the standpipe on the left side. This can be just a short length of PVC (1" worked for me), siliconed to the bottom. You'll notice the u-tube extends nearly to the bottom of this side as well. If it doesn't, get one that does. The standpipe regulates the water level in this side. When power fails, the water level doesn't go below the standpipe, so no siphon lost, no issue.

Make sense?

 

There is a stand pipe outside. Maybe it or the U tube is not long enough. The U tube does not pass the standpipe. How should I fix this

 

The times I have seen U-tubes break siphon is when the overflow rate is being pushed to the max and turbulent bubbles are dropping into the overflow (in the tank side). Those bubbles get sucked into the tube which cause the siphone breaks. Even if the tubes are set up to proper submersed levels, if bubbles get sucked into the tube, the siphon will break. I think the safety net would be the suction method that CPR employs. Not having any precautionary catches is like betting against yourself when something may go wrong.
Deron, If you want a CPR overflow, I would suggest going with the largest one that can fit in your system, or go one size larger. I use a CS-100 in my 150G tank, which handles 800GPH.

 

Before messing with the standpipe and the u-tube, I would first determine where the bubbles are getting trapped, from the tank side or the drain side. If they are getting sucked in from the tank side, you can add filter floss to the tank side overflow to lower the turbulent bubble entering the overflow to lessen the chance of bubbles getting sucked into the tube. If it is happening on the drain side, then make sure the U-tube end is lower in the water than the top of the standpipe.
Personally, I like having the safety net of having the airlifter in place just in case something happens.

 

The problem is that the U-Tube doesn't go past the standpipe. While trapped bubbles could be AN issue, it is not THE issue here.

From a physics standpoint, what I'm about to ask doesn't make sense, but just for kicks; if you turn your U-Tube around, does it then go past the standpipe on the drain side?