overflow box prob.

[Jawbone]

Well here is a thought why dont you just get a smaller Diameter J Tube since its Inside diameter would be smaller then the water would flow through faster. Thereby removing your air bubbles. I dnot think there is a problem in your system just because air bubbles exist does not mean that you need to buy a larger pump. Hell my faucet drips does that mean the water company needs to put me on a different water line. Again not trying to start an argument but the J tube that you are using my be fine for a flow of 800 GPH but if I had a 2000 GPH pump would the same tube work... I am not sure. does that mean I need a new pump... No, probably just another J Tube

JMO

 

[ZigZagZombie]

Never thought about a smaller diameter tube.

That just might be the way to go. I'll let you guys know if it works.....Thanks again for all your help.

 

[DK]

ZigZagZombie,

Instead of drilling your U tube or using the CPR overflow with its inherent design flaw. Take a piece of airline tubing, thread it through the U tube to 1/2" past the midpoint (or highest point) and connect the other end to a powerhead. I have used this method for years.

The major design flaw in the CPR overflow is that if the air line tube gets loose, you loose the siphon AND if your system goes off for an extended period of time, the water will back siphon through the airline tube to the level of the end of the airline tube in the water. In say 3 to 6 hours, it could drop the tank level a couple of inches assuming the powerhead is in the main tank. So, you have to make sure the sump can handle that amount of water!!!!!!!

I just created my own overflow with the powerhead in the overflow so no worries!!!!!!

 

[KanUCme]

I had this problem once. You have to figure out how the bubbles are getting in the box. If the bubble gets in the box it might get stuck at the top and then more bubbles build at the top. You might need a smaller diameter U-tube. Or lowering the overflow box so that more of the inlet is under the surface, this helps to get rid of the bubbles. You shouldn't need to hook up a venturi to the U-tube.