Overflow needed?

[rigby]

I'm looking to build a sump/fuge combination below my tank. I was hoping to use just a siphon effect down to it but I've gotten the advice that I needed an overflow for this purpose, do you agree? If so what overflow do you recommend? I cannot drill the tank. Please and thank you for your help!

 

[fender]

An overflow is much better than just a siphon tube and is the preferable method of getting water down to a sump if drilling is not an option. The overflow will skim surface water where most of the nasties are, most will hold a siphon even if there is a powerloss, and are tunable.
CPR makes a good model but they are pricey.
Here is some good info on sumps and overflows
http://reefkeeping.com/issues/2003-01/gt/index.htm

 

[jacksonpt]

An overflow is the preferred and recommended way to go, but it is not absolutely necessary. You can do the gravity fed thing, but you'll have to make sure your return pump's flow rate matches your gravity pull rate (i.e. make sure water is going into the tank at the same rate as it is leaving the tank).
As for overflow boxes, the big 3 seem to be Amiracle, Lifereef, and CPR. From what I've read, people either love of hate the CPRs. I've never heard anything bad about Amiracle or Lifereef boxes.
FWIW... I have 2 CRP boxes. They are pretty good. Not great, but they get the job done. Overall, I'm pretty happy with them, but if I had it to do over again, I'd probably look elsewhere - most likely the Lifereefs.

 

[fender]

Hey Jackonpt,
What problems have you had with the CPR units? I am going to be buying an overflow myself pretty soon and want to avoid wet carpet as much as possible.
I noticed the lifereef units are cheaper.

 

[shanev]

Like said dont try the siphon, you will eventually wind up with a wet floor. While you may be able to match the flow for a bit pumps vary from time to time. Also if the electricity goes out you will darin the main tank to the point of the siphon. If your not around when it comes back on all the water in the sump will go back into the display and leave the pump running dry.
Long story short, go with an overflow.

 

[beaslbob]

If you want to save a little money you could do a diy overflow box. Whatever you do you need to insure the a power outage and the return of power after an outage does not produce a flood.

 

[jacksonpt]

Originally posted by fender
Hey Jackonpt,
What problems have you had with the CPR units? I am going to be buying an overflow myself pretty soon and want to avoid wet carpet as much as possible.
I noticed the lifereef units are cheaper.
I haven't had any problems with the overflow box, exactly. There are a few things that annoy me about it, but I haven't had any problems - no floods to this point, and both have seen 1 powerouttage (while I was away on vacation). There's a jinx if I've ever seen one
Anyways...
With any overflow, as water leaves the overflow box and flows into the downtube towards the sump, the water replaces air in the downtube. This air needs to escape, or else you will get a gurgling sound. Check out this thead for more on this.
The other thing is that on top of the overflow is a

[hr]
. You are supposed run air tubing between that

[hr]
and a powerhead. The powerhead will suck the air out of the overflow to maintain the syphon. I've had some issues getting the powerhead to suck out the air. If the powerhead is too deep, for some reason it won't pull out the air - might be an atmospheric pressure thing, but I'm not sure. This is my biggest annoyance, as it could lead to a problem under the right conditions.
If you have any other questions, let me know.

 

[bigmac]

If the CPR overflows still require a powerhead to startup then its going to fail sooner or later. I use a U tube overflow for 10+ years without one failure.

 

[rigby]

a U tube overflow you say, what is that exactly?