U-tube on drop-box?

[WRASSER]

I have two U-tubes on my drop box and one keeps breaking sucktion, what if any is the solution to solve this and stop it from happening?

 

[fungia]

it is sometimes hard to balance two u tubes. maybe get a bigger single u tube? i have put very small water pumps on u-tubes that helps to keep air from getting trapped.

 

[Anonymous]

It usually happens when there isn't enough flow to push the air out. If box can handle additional flow, then increasing ot will help get rid of the trapped air from breaking the siphon.

 

[WRASSER]

when i siphon to start, i make sure there is no air in the tube. it work for a few days then breaks. its been funny cause now it switched tubes.

 

[Len]

Air always gets trapped in U tubes over time. It's as inevitable as death and taxes. CPR now has an optional integrated pump to prevent air bubbles from building up in their overflows. As fungia said, you can probably DIY something similiar, or switch to the CPR "C-siphon" overflow system.

 

[WRASSER]

anybody have a site to see what it looks like :?:

 

[mike90]

i would try using just one tube. it sounds like it's sucking too much water too quickly. there for leaving just air for the second tube to suck

 

[Ben1]

Air always gets trapped in U tubes over time. It's as inevitable as death and taxes. CPR now has an optional integrated pump to prevent air bubbles from building up in their overflows. As fungia said, you can probably DIY something similiar, or switch to the CPR "C-siphon" overflow system.

I have a very different opinion on this. I feel the CPR overflows are very faulty and you should never depend on a powerhead to keep the air out. The trick is to match your return pump to your overflow. My lifereef overflow is a dual tube and can handle 1400 GPH, my return after head and piping loss is 1100, bubble race through the tubes. JMO

I have never had either a single or double lifereef overflow loose its syphon in many many years even through many power outages. It is always the ones depending on pumps to pull out the air I here of failing,

In anycase I agree you probably dont have enough return to keep up with both U tubes, try just one. Or increase your return from the sump.

 

[WRASSER]

can you give me an ideal to increase the flow. I already increased my tubing size and took the 90s off the uv light :?

 

[Ben1]

Use the head loss calc and determine the actual amount of water being returned first...

http://reefcentral.com/calc/hlc2.php There is one on RDo also just can never find it.