Sump & Hob Overflow help!

[Chiefmaster30]

I have a 30 gallon sump on my 120 gallon dt. I broke my old hob overflow box so I replaced it with a dog one. It has 2 "U" Tubes instead of 1 like my old one. After I primed it 2 days ago one of them got an air pocket back in it but one was still good. So I resiphoned the air pocket out of the one again so they'd both be air free. I just noticed today now both of them have air pockets again. What is causing this?

 

[saltyfilmfolks]

Bubbles from the box inside the tank. The water is probaly low in it.
I eventually just went with one tube.

 

[Chiefmaster30]

I was thinking of doing that. Why is there 2 anyway?

 

[ReeferMaddness843]

The other issue I've seen cause a bubble to form over time is flow being too slow from the return not being able to push the bubbles through before they would settle in the top of the U tube.

 

[saltyfilmfolks]

Higher flow rates I believe .
If it really pushing a lot of water you need it.

So like me your probaly way under what it's rated for.

 

[Chiefmaster30]

Ok! Yes that makes perfect sense! Thanks!

 

[DDanis60]

To stop the bubbles from clogging up the u-tubes, you have two main options if you want to keep using them. Either a: turn the return pump flow up much higher to warrant having 2 tubes for the extra flow.. or b: remove one and only use one tube. Reefer madness called it with the flow being too weak through the tubes. It's like salty said, the 2 tubes are for much higher flow systems. Too bad if your return is already maxed, you kind of only have one option. Good luck!