Advice for plumbing a sump

[firerock]

After some researchs, I'm thinking about adding a sump to my tank. Although the plumbing part seems reasonably easy, but there are 2 things that I am concerning about.

My tank is not drilled, so I need to get an over the counter overflow box from CPR. It ranks the flow rate about 800GPH. From my understanding, I would need a return flow that will match the drain rate. But, the Mag 9.5 return float for 4' is 850GPH. Will that cause any problem to my setup? I guess what I'm trying to say is that it is very hard to match extactly the drain & return rate. If drain rate is higher than return rate, what would happen? And what if my return rate is higher than the drain rate? Also, I really want to avoid the dreadful siphoning sound. How can I avoid that with the hang on back overflow box?

My second question is that how does the air pump avoiding the break up of siphon? I've seen a airpump design that will prevent the problem on the CPR overflow box, but how does that work? Is it a reliable solution to break up siphoning? I've read many horror stories about overflowing display tank due to the problem. I get into big trouble if there is any flood.

Are there anything else that I should be worried about? Or do you have any other suggestions as for which overflow box or pump to use? I am thinking about Mag 9.5 because it can be run both inside and outside of the tank, so I can take it out of sump when it is really hot in summer to reduce the heat buildup. Any comments?

Thanks for any info you can provide.

 

[glaudds]

If drain rate is higher than return rate, what would happen? And what if my return rate is higher than the drain rate?
Your overflow will only drain what your pump will return. If your return rate is more than your overflow rate, then you run the risk of overflowing your tank because the overflow doesn't keep up with the return. You can resolve this problem by teeing off some of the return back into your sump.
My second question is that how does the air pump avoiding the break up of siphon? I've seen a airpump design that will prevent the problem on the CPR overflow box, but how does that work? Is it a reliable solution to break up siphoning? I've read many horror stories about overflowing display tank due to the problem..
The air pump is used to maintain the siphon and remove the buildup of air in the overflow. This will allow the overflow to work in the event of a power outage. A maxijet powerhead attached to the overflow also does the same thing.

 

[firerock]

glaudds: Thanks for your reply. Your answer makes sense to me, but how come you will hear those loud slurrping/siphoning sound in some overflow designs and not on others? What's the solution for that?

Also, how do I attach a maxijet/powerhead to the overflow to prevent siphon breakups? Do I simply insert the airline tube inside the reverted "U" shape loop?

Thanks again for your help.

 

[Gooli]

firerock...i dont have personal experience with overflow boxes, but if i was buying one i would get the one everyone raves about:

spend a little more and sleep well at night!
http://www.lifereef.com/siphon.html

 

[firerock]

gooliver: thanks, I will look into that product.

 

[DANNY G2004]

I have a CPR overflow I can sell you $80 with pump

 

[glaudds]

<a href=showthread.php?s=&postid=6834693#post6834693 target=_blank>Originally posted</a> by firerock
Also, how do I attach a maxijet/powerhead to the overflow to prevent siphon breakups? Do I simply insert the airline tube inside the reverted "U" shape loop?

Though I've never done it, some people silicone an airline at the top of the U tube. If you push your overflow at its maximum rate, then there is less chance for air bubbles to accumulate in the u tube.

 

[Charles99]

This statement by glaudds is incorrect:

"Your overflow will only drain what your pump will return."

This is only true if you are using a built-in overflow, where the water drains into your sump below. With a hang-on, like the CPR you mentioned, a siphon is used to "suck" water out of your tank.

You still run the challenge of matching flow rates. Just because a pump is rated for 800 gph, doesn't mean that is what you are getting. There is a factor such as head-loss that comes into play. Basically this concept works in a negative way regarding pumping losses. Pump location relative to the return outlet (height between the two) or plumbing bends add to the head loss.

Hard line your return system w/ PVC pipe (really cheap to do) and throw in a PVC gate valve (has a faucet handle like the one located in your front yard). You can control the rate at which the water travels back to your tank from your sump. Always pick up a pump that is a little bit higher than your overflow rate. The pump you are looking at is perfect.

PS. I have 2 siphon style overflows that I use which I put together using old parts from a canister filter (hard tube and screen).

good luck!

 

[glaudds]

Charles, you are correct that you must factor in headloss and plumbing bends to determine a pump's true return rate.

However, a properly designed hang on overflow will drain only what the output of the return pump is (assuming the output is not more than the rated GPH of the overflow). Though most overflows function best close to their rated capacity (to prevent air bubble buildup), they will function at lower drain rates also.

The function of the siphon in a hang on overflow is to get the water over the top of the tank from the inner overflow box to the outer one...not to "suck" water out of the tank. Hope that clarifies my previous post.

 

[Charles99]

Thumbs-Up.

 

[firerock]

Thanks guys for your help.

 

[Danger731]

look into life reef, - check my gallery