How safe are HOB overflows?

[FlyPenFly]

The eShopps overflow quality is inconsistent for sure.

A lot of people use a Herbie overflow without an emergency... some won't flood, some will. Doesn't mean it's a good idea.

 

[MondoBongo]

The u-tube siphons need to be re-primed if they sit for awhile with no flow ( an hour or so) and the cpr with the aqua lifter is self priming.

i've never seen or experienced this. the u-tubes on my overflow boxes stay primed for as long as i leave them be. there is a secondary weir on the "dry" side that keeps the water level up and ensures it does not lose siphon.

i have two e-shoppes overflows, neither have this issue.

as sirreal63 said, the cpr is deeply flawed. i don't want a rube goldberg device to start my overflow siphon.

 

[wildman926]

The CPR weir is the very epitome of a flawed design. Any product that requires another product to ensure safe operation is a poorly designed product.Over the years more floods have been attributed to a CPR than any other brand out there. The Aqualifter is another weak point, they work good in the beginning but it is a matter of time before it looses suction, the line clogs with algae or completely fails requiring a rebuild. Where will you be when it fails? If at home no biggie, but if you are away from the tank it can be an issue.

The U-tube design does not rely on any band aid to correct the poor engineering. Properly set up it will not lose suction, the tube will not lose water and any bubbles that appear will flow through it. It can be problematic if not set up correctly or too weak of a return pump is used, but these are not design flaws, they are user error.

I used hang on back overflows for many years, I never had a failure that wasn't because I did something stupid. I researched all of the different hang on overflows before I decided on the U-tube design. The number of failures of the CPR/Aqualifter design used to be fairly well known, you will find a lot of them in the archives here.

Very well said, as always when getting advice from sirreal63.

I have always U tubes for overflows, and don't like drilling glass. Something about that just sends off alarms in me.

For a fail safe setup, get a pump stopper kit from Aquahub. HERE is where you can see it. I use them on both my tanks, modified for my use.

 

[AkoAung]

I prefer the u tube style overflows cause they don't depend on a pump to work.

Cpr worked for me with no problems but just make sure you have a spare aqualifter pump incase it quits working.

I think the main reason is I had trouble with the CPRs lift pump, on more than one occasion and water on the floor more than once with it. My U tube style I have never had a issue with. Yea I have to clean the tubes every so often, and manually start the siphon with a air line

Gentlemen! I read this thread because I recently purchased a CPR overflow with the airlift. I thought the lift was to get the siphon started initially but as you all stated, it has to be running all the time for the CPR overflow to work. And I am concerned about the worst case scenarios about airlift stopping and water overflowing when I'm not home. I've come up with a simple solution to this.

CPR is a U-tube siphon without the one-way air valve. The simple solution is to attach a one-way air valve to the CPR with the use of a short tube and use the other end to create the siphon. Once the siphon is established, then remove the air lift from the one-way valve and presto. you have a U-tube overflow box.

Using the cheap <$0.99 one way air valve wouldn't even require purchase of an air lift. And CPR would need to be cleaned, just like U-tube overflow boxes in case of algae buildups. Sounds good?

 

[sirreal63]

The problem isn't initial starting with the weir, it is continued use and air bubbles do not flow through them correctly, they tend to collect in the corners, as they collect less area is available for flow, reducing the flow until the tank overflows. Bubbles are normal and expected. The CPR design allows for a lesser flow at the corners, which is where any bubble will collect.

 

[hijinks]

I had a aqualift that almost failed on me and I learned my lesson.

Make sure you clean the airtubes monthly or salt creep blocks the aqualift from doing its job and air bubbles begin to form in the overflow box.

 

[dwculp]

Thanks for the advice everyone. IT makes me feel a bit more comfortable going with a HOB overflow. Based on the replies I will investigate the livereef overflows.

 

[sirreal63]

You can't go wrong with the LifeReef, it has the longest record of success. Match it up with the appropriate pump and enjoy some peace of mind.

 

[swk]

The eshopps work fantastic too if you're on a budget

 

[degibson84]

The aqua lifter pump hooked up to it basically. It works without the pump but the pump gives it some redundancy. The u-tube siphons need to be re-primed if they sit for awhile with no flow ( an hour or so) and the cpr with the aqua lifter is self priming.

Not true. I unplug my return pump for multiple hours during maintenance and have never had to prime my u tubes. The only time I primed them was when I set up the overflow

 

[Drae]

Not true. I unplug my return pump for multiple hours during maintenance and have never had to prime my u tubes. The only time I primed them was when I set up the overflow

What kind of overflow? I had eshopps before the cpr and it needed to be primed again after awhile.

 

[degibson84]

I have been running an eshopps for around a year.

I tried the CPR but you have to rely on the aqua lifter to pull the air out. If it doesn't turn back on after a power outage you end up with a flood. Trust me that wasn't fun.

My eshopps has been primed once. That was durning setup. Haven't touched the u tubes since. When I have a power outage the siphon is always there and when the power comes back on it starts pulling water

 

[Drae]

I don't run hob overflows anymore but when I did I never had a problem with the cpr. Different situations for different setups I guess. Drill drill drill! Lol