How well do those HOB overflows actually work?

[biggredd]

I have a CPR and it is just ok. I have a couple of small bubbles that are in the top of the box but I have a rio 600 pump in my sump and a long air hose going up to it. It is constantly pulling that air out if needed. One thing though. If you go with CPR I would suggest the pump to get it auto syphoning after a power outage. But if you do decide to do that put it in the sump. I turned the power off to work on it and the water level dropped below the level of the overflow box just fine and stopped there, I drilled holes in my return pipes so I wouldn't have back siphon, and then I realized an hour later that the pump that I had right next to the overflow box with the provided air tube started back siphoning and I spilled over and leaked into my basement. I put the pump in the sump and used a long air hose to attach to the

[hr]
on the top of the overflow. works like a champ now. The only thing now is I'm concerned I may not be running at capacity.
also, another thing they DON'T tell you which I wish I knew before I bought it is that the fish screen and the filters combined can lead to a 20% loss of flow. This is straight from their tech support on C P R U S A dot com. I posted a question and they told me that. Kinda pissed about that. Might remove my filters to increase a little flow.

 

[shrmnator]

Originally Posted by Hurt
Shirminator, I will promise you your flows aren't close to being matched if you are getting airbubbles in the top of the U-tubes. The water is not going through it fast enough and the air bubbles don't make it all the way through. That's why they settle in the top. If you clean out your prefilter, your return pump won't be as restricted and will be able to to put more flow back into your DT to properly match with the overflows capability. But, if you don't want my advice, your overflow will fail. All I am saying is your flows are surely not matched if you are getting airbubbles in the top, I will guarentee that much.
i guess your overflow box defies gravity and the water overflowing into it doesnt splash slightly to make bubbles that can make their way into the tube...

 

[hurt]

Originally Posted by shrmnator
i guess your overflow box defies gravity and the water overflowing into it doesnt splash slightly to make bubbles that can make their way into the tube...
Not at all...The difference is mine is properly matched so the flow is fast enough for the bubbles that enter make it all the way through, instead of being caught in the top of the U-tube like yours are due to the fact that your flow is obviously not fast enough for what your overflow is rated for. If you don't want to take my advice so be it...I was only trying to help you out and prevent the imminent disaster you have on your hands...If you don't believe me, believe the others who stated the exact same.

 

[reefnut]

Originally Posted by shrmnator
i guess your overflow box defies gravity and the water overflowing into it doesnt splash slightly to make bubbles that can make their way into the tube...
I'm not sure why you got offended (I'll have to read back through the post) but what Hurt is saying is correct. If the flow is not strong enough to push the bubbles through then they will build up and it can fail. If you increase the flow so the bubbles do get pushed through then it will not build up. If the tube is clean you can watch and see if they are going through the tube or not.

 

[shrmnator]

im trying to figure out how it seems i got offended.. i simply stated a fact as to how the bubbles end up there.. my tube is full of coralline algae and very hard to keep clean since the coralline just comes right back after a good scrubbing.. maybe the bubbles kinda stick to it, but at first they always just flow right thru the tube but eventually accumulate after long amounts of time.