Overflow question

[chrisd]

I am going to be switching over to a sump for my 54 gallon corner bowfront and because my tank is not drilled and is made of tempered glass I'm going have to invest in an external overflow. I've been doing some research and it appears that the Lifereef overflows seem to be the preferred brand to go with. I'm going to have Bow Valley Aquarium build me a 18gallon sump and was looking at getting a Rio20H which would give a flow rate of around 990gph at 4ft head. My question is would a dual overflow with a flow of 1400gph be too big for this setup? The single overflow only has a flow rate of 700gph. I've read in certain areas that the overflow will match your pump output but I'm not real clear on if that is true or not. Any advice would be greatly appreciated. Thanks.

Chris

[Delphinus]

Hi
The overflow will match the pump rate. Two considerations to take into account; 1) if the flow is too slow you run the risk of air bubbles accumulating in the U-tube. Enough accumulation can break the siphon eventually. You can reduce this risk with a higher flow, if the water goes fast enough it will just push the bubbles through. The other consideration, 2) if the flow is too fast you can run the risk of it not being able to keep up. You can add another U-tube though to keep up.

HTH

[Fish]

Chris,
Hey bud. Do you happen to have a link to that pump? I was going to try and run the numbers through the headloss calculator here:
http://www.reefcentral.com/calc/hlc2.php
I can't find the pump though. My gut is that you might want the single tube box, especially if your sump is going to be smaller. Over 700 gph through a smaller sump will probably result in some wicked microbubbles. HTH.

Cheers,

- Chad

[chrisd]

Thanks for the input guys. The reason I'm giving the Rio a go is because back a couple of months ago when I was pm'ing with Danny Zubot i found that he had the same tank as me and greatfully offered some advice and info on his sump setup. Now I'm pretty sure he has a drilled tank and from your answers it kind of looks like I'm in a grey zone where if I go with one or the other I'm looking at the possibility of something going wrong. What would either of you figure is the safer choice...going with a smaller pump and the single tube? I understand the Rio 20 has a lot of power and was hoping to get rid of my powerheads in the display tank. I also understand it's quiet. If the smaller pump is the way to go can you offer some advice on a good quiet pump with about 700gph(if you feel that's the right size)at 4ft head. I'm gonna pull my hair out if I have to go back in and research this whole thing again. This plan is still in the research and development stage so I'm open to scrapping the whole thing and trying a different plan. Again, any advice will be very helpful. Thanks.

Chris

[Fish]

Hey Chris,
I have been looking around for the pump that you mentioned and I can't find any info on it anywhere. The largest rio pump that I found is called the Rio3100HP ("High Pressure"). It lists as 900gph at 0" but drops down to 700gph at 3" head. Rios have never gotten very good reviews in terms of reliability I owned a Rio2100 that just crapped out one day and wouldn't start. I'd find out exactly which Rio Danny is using and double check the head-loss. It might still meet your needs and be pretty affordable. I also know a lot of people use submersable Mag pumps. It looks like a Mag9 at 4" head with 3 90degree elbows makes about 650gph after losses. They sometimes come up for sale here for around $100.
What are the dimensions/volume of your sump? I have a feeling that you might be blasting too much water through your sump if you want to create all of your main-tank flow with the return pump. If I were you, I would use the single tube overflow box with a 600+gph pump and then make up the rest of your flow with a second pump. An external pump on a closed loop would be great and would enable you to get your powerheads out of the main. A more affordable solution would be to just use one of the powerheads you already have to supplement the flow from the sump return. Since you would have an overflow box, you would no longer need to have your powerhead at the surface of the water and could lay it on the sand in the back of your tank behind the rocks. All that would be visible is the electrical cord running up the back corner and I bet you wouldn't even notice it. Sorry this post is so long - I should have just got on the phone and called you up :biggrin: .

- Chad

[chrisd]

Yup, I think that would be the best way to go Chad. Thanks for the input. I'll just keep it simple and avoid the headaches. :smile:

[danny zubot]

Chris, what brand is your tank? Mine is an Oceanic, and only the bottom is tempered glass. Your could still have a hole drilled into the side like I did, and fabricate an internal overflow with ABS piping. Just another option to consider. With the correct sized overflow there will be less noise, because I know that was an issue.

[chrisd]

Acually Danny I thought you had the same tank as me but I guess not. I've got and All Glass 54 and unfortunately I can't drill it. So it looks like an external overflow until I one day buy a new one.