How Do These Overflows Work?

[theotheragentm]

Since I've never seen one in person, I don't know how these work exactly. Can someone explain it to me?

 

[MT79]

Water is siphoned from the tank into the back of the overflow, where it drains into a sump. Air bubbles tend to get trapped and accumulate in the chamber the airline is attached to, breaking the siphon. The pump sucks air out, maintaining the siphon and keeping the water flowing. Those Air Lifter pumps are notorious for failing rather quickly. A much better choice is a Maxi-jet 1200 power head w/ a venturi attachment. It is much more reliable and powerful.

 

[nicksgirl]

If you hve not already purchased this set up, reconsider carefully. It is beautiful but that seems to me to be it's most appealing quality.

I am running it on my 55 gal. and I have had several overflows onto the floor. I've only had the system up a few months and my AquaLifter pump has failed repeatedly. I now have three of these pumps which I clean (by running water and vinegar through them) and rotate into use every two or three weeks. This seems to have solved the failure problem but it's kind of a hassle.

 

[mulron]

I've been running one of these for some time now. Once you get by the little quirks they are good.

First off don't buy the airlifter. They just plain suck. Hook the overflow up to a PH and it will do wonders.

Second I would purchase a float switch. (which I would recommend for any overflow not built into the tank).

http://www.marinedepot.com/md_viewItem.asp?idproduct=UL1111

That is what I'm running on mine.

With both of these in place I have had no problems. About every 2 months I replace the air tube and clean out the connections. Other than that. works like a charm.

 

[MT79]

First off the aqua lifter stinks as I said in my first post. You'll need a maxi-jet 1200 w/ a venturi kit like this-http://www.premiumaquatics.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=MJ-VENT&Category_Code=
Just place the PH in the sump and run the airline up to the overflow.
As far as floods go if your sump system is set up correctly you should never have a flood regardless of whether the overflow fails or the return pump.

I've been using a CPR overflow w/ a MJ 1200 PH and the venturi kit I linked to for over two years w/ out a single failure. Just clean the nipple on the overflow every couple weeks.