# PVC Overflow



## hidenseek (Nov 13, 2005)

Hello all. I just made a pvc overflow out of 3/4" pipe and the flow is very poor. I'm using a QuietOne 2200 which is rated for 581gph at 0ft head. As you can tell from the picture it's about four feet below the surface of the return line. I've read that 3/4" pvc should give a couple hundred gph flow rate. However, it's no where close to those numbers I've seen stated. I have a ball valve on the return line to regulate the flow and that valve is barely cracked open and maybe only providing about 30-50 gph return. Also, I'm having a hard time regulating the overflow with the return. How am I supposed to get these flow rates dialed in so they match eachother? There's thousands of people using sumps and I'm sure there has to be some kind of trick to this. How can I increase the flow without upping the diameter of the pipe? Just add another overflow? Or do I need to up the pipe diameter to 1 1/2"? Thanks for any help.


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## duaneS (Aug 31, 2006)

Maybe I don't understand your post,....but the flow to, and from your tank should have an equal relationship.
Your flow is only going to be as strong as you allow the pump to be opened up (the line back to the tank). 
If your return line is almost closed (the way it looks in the photo (that is if I see it right)), there's no way you can get a strong flow out of the tank. 
To create the max flow both lines should be open full bore.
Although, If the pump is rated at 582 gph at 0 head, at 4 ft of head it will produce much less.


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## pjgamber (Jul 14, 2008)

duaneS said:


> Maybe I don't understand your post,....but the flow to, and from your tank should have an equal relationship.
> Your flow is only going to be as strong as you allow the pump to be opened up (the line back to the tank).
> If your return line is almost closed (the way it looks in the photo (that is if I see it right)), there's no way you can get a strong flow out of the tank.
> To create the max flow both lines should be open full bore.
> Although, If the pump is rated at 582 gph at 0 head, at 4 ft of head it will produce much less.


exactly

you want your ball valve on the line from your pump to the tank

that way you can adjust the flow rate on your return. until it matches what your over flow can handle

but fyi 3/4" return line can flow a lot more than your 3/4" overflow line.

on my tank i have 2 1 inch over flow lines and 1 3/4" return line hooded up to a 900 gph pump. the 3/4" line easily keeps up with the double 1" inch lines because it is under pressure


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## hidenseek (Nov 13, 2005)

ok sorry for the confusion with the pic. the pic was more of a reference to my set up. it's not currently running in the pic. both the overflow and return lines are 3/4" pvc.

on the other question though regarding the overflow flow rate. Can someone please enlighten me on how to gain more gph from my current setup, or tell me to just beef up the overflow. Thanks again guys.

P.S. the pump curve for my pump it states that the flowrate is approx. 380 gph at a 4 ft head.


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## willny1 (Nov 17, 2008)

With each 90 degree elbow in your line will reduce flow some what. So it will be less than 380. There are numbers out there that tell you about how much but I cant locate them.

Is you pump restricted with the ball valve? You need to open it up all the way. The more water going into the tank, the more water your 3/4 inch over flow should be putting into the sump. As long as the 3/4 inch pipe is rated above what your pump can flow, you should be OK.

3/4 inch pvc should flow up to 600 GPH I believe. W/O restrictions (elbows).


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## hidenseek (Nov 13, 2005)

So you're telling me if I turn open the ball valve full bore and let my pump run freely that the overflow will flow more water? This is not right. Don't know where you got that info from. If I open the ball valve to allow for higher flowrate on the return line than the overflow, all I'm doing is overflowing the tank. Trust me I did it! 
The flow rate for 3/4" pvc is 660 gph without restrictions. Does anyone know the gph lost at each bend?


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## willny1 (Nov 17, 2008)

I just built an over flow about a month ago.

I will give you the info I have learned.

In my searchings, I found there is thinner I.D. PVC 3/4 which has more flow rate. The outside is the same size (3/4). The inside is thinner which allows more flow. I believe its scheduled 80 instead of the standard scheduled 40 which is thicker.

Also, Certain types of elbows have greater restriction inside them than other make of PVC. I noticed this when looking at the homedumpster vs Lowes stock. Obviously, you want the elbow that stays 3/4 because whatever the I.D. of the elbow is, that will affect your flow.

The over flow 3/4 pvc will flow 600 in perfect conditions. (no bends, full siphon)

Over flow isn't a siphon so it will flow less.

I tested my flow rate at around 500-550GPH. Using 1 inch thinner I.D. PVC.

Take this with a grain of salt. It is just what I seem to have remembered in my research.


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## hidenseek (Nov 13, 2005)

Do you have yours up and running still? I measured the ID of my pvc and it is 3/4" ID pvc. How does your overflow differ from the one I made. I think I understand all the physics and what not involved with the pvc overflow design being that it's run off of gravity and may not be perfect. With all that being said I'm still not able to achieve what everyone else seems to be getting. Thanks for all the help btw. Can you share pics of your setup if you got em??


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## hidenseek (Nov 13, 2005)

Do you have yours up and running still? I measured the ID of my pvc and it is 3/4" ID pvc. How does your overflow differ from the one I made. I think I understand all the physics and what not involved with the pvc overflow design being that it's run off of gravity and may not be perfect. With all that being said I'm still not able to achieve what everyone else seems to be getting. Thanks for all the help btw. Can you share pics of your setup if you got em??


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## Mcdaphnia (Dec 16, 2003)

There is a pretty simple explanation why you would have problems with this overflow. It is a design that works well in a system of many tanks. The return water is split up between many of them, usually just a pinhole spraying a jet of water into each tank. The overflows collect water from each tank and contribute it to a 4" pipe or a run of plastic rain gutter that leads back to the sump. If all of the water is going to return to one tank, then you need to build your overflow out of laerger diameter pipe. Inch and a half is commonly used, depending on your pump capabilities.


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## avy1219 (Jan 8, 2006)

on the top of your over flow, you have what appears to be air line tubing coming out. Is that attached to an air line check valve?


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## willny1 (Nov 17, 2008)




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## willny1 (Nov 17, 2008)

One thing I should mention, make sure it is air tight. Silicone around where there airline is coming out of the top of the overflow. Airtight!

There has been a few people on this site that has used 3/4 pipe. I remember them saying they would have used 1 inch if they had to do it over again on this forum. I don't know how much they got it to flow at though.

Honestly, with the size of your tank and sump, I would use 1 inch.

On my system, I didn't install a ball valve. As long as my 1 inch over flow can handle my pump output. Which it does and never needed to tune the flow.


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## hidenseek (Nov 13, 2005)

avy1219 said:


> on the top of your over flow, you have what appears to be air line tubing coming out. Is that attached to an air line check valve?


yes the airline is connected to a check valve!


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## willny1 (Nov 17, 2008)

One thing I should mention, make sure it is air tight. Silicone around where there airline is coming out of the top of the overflow. Airtight!

There has been a few people on this site that has used 3/4 pipe. I remember them saying they would have used 1 inch if they had to do it over again on this forum. I don't know how much they got it to flow at though.

Honestly, with the size of your tank and sump, I would use 1 inch.

On my system, I didn't install a ball valve. As long as my 1 inch over flow can handle my pump output. Which it does and never needed to tune the flow.



Also, The greater the distance from the water level to the where the T is in the overflow pipe, the greater the siphon/suction you will achieve.


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## hidenseek (Nov 13, 2005)

I have everything cemented in place and yes the airline is siliconed tight. Everything should be as to spec and I will be testing again after I eat some dinner. Or as I call it "hobby fuel"! Yea that was cheesy!!


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## avy1219 (Jan 8, 2006)

Ok then ya got me. Just to be sure double check to make sure it is in there tight. That is the problem that i had with mine. So maybe even double check all your connections to make sure they are not letting air into the setup. Air is the Devil  After that just start sucking the air outta the check valve.....good luck


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## hidenseek (Nov 13, 2005)

Alrighty. So everything is all glued up ready to go. I tried to suck on the open end pipe that stick up above the tank to keep the suction going. Well, I thought I was going to die huffing in all those fumes from the pvc cement!!!  =D> The cement I used is the potable water safe stuff so no worries there. I tried filling the whole rig up while blocking the outlet at the bottom and nothing yet. I also sucked all the air out of the check valve, but nothing. I have to wait a while for the fumes to subside to give it another go. Wasn't expecting that that's for sure. I'm not done yet though. I'll let ya'll know when I'm out of ideas. In the mean time I wouldn't mind hearing any more ideas you all have as to how I am supposed to get the outlet and inlet matched up (flowrates).


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## hidenseek (Nov 13, 2005)

Well, the flow rate is still real slow so I'm going to have to build another one out of 1 1/2" pvc tomorrow. That should flow a little better I hope. I want to have a high return rate so I can have a spray bar to create a good underwater flow for my loaches. They like that sort of thing. I have two powerheads also so I'll be using those as well. Thanks for all the help. Looks like I have some more reading to do. Even having read that 70 page long thread on MFK.com!!!


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## hidenseek (Nov 13, 2005)

Okay. I still have my overflow running and have another question. After a couple minutes at a time a big air pocket developes and comes shooting into the sump tank. Is this normal? All the while I do see lots of air bubbles coming out of the overflow line into the sump tank. Should there be this much air in the overflow piping?


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## hidenseek (Nov 13, 2005)

Okay doesn't seem like anyone is paying attention to me, but I'll update anyways. I trimmed back on the intake pipe so it is lower under the surface of the water and finally discovered how to increase my flow rate!! Only problem now is the immense amount of air being sucked into the overflow contraption via the open end pipe that sticks up above the upper U section. Hope you get the visual here. It's the open end that isn't in the water. If I cap that off with a slip cap and drill a hole in the cap that will only work to some degree to lessen the noise. I can also put an over sized cap on the intake pipe that is inside the tank that will break the tornado effect and get rid of the noise coming from that aspect. If I push some kind of filter floss or cloth down the open ended pipe on the outside of the tank will that prohibit the overflow from re-establishing the suction after a loss? Thanks again.


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## KaiserSousay (Nov 2, 2008)

Been there..done that..if you do a search on this you will be overwhelmed by the number of folks who have made these systems, with varying degrees of success.
Once mine was in, flowing, the amount of time I spent tinkering, to get the gurgle down to liveable levels(her`s not mine  )quickly added up.
You have already done all the same things I did, still noisy.
I tried every version of stand pipe, gurgle buster I could find.
I finally gave up and went with a skimmer/overflow and ALL noise was gone.


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## hidenseek (Nov 13, 2005)

Well I hear you there Kaiser. But on the other hand you're only 1 of thousands that have made this overflow to work how they want it to. I'm sure there's at least 1 person in this forum that can help out with some kind of success story on getting the noise down. I've read your post too by the way so I know your gripes, and her's! My wife was like what the **** is that noise?! Had to try to explain all the knowledge I had.

Someone with some success on this please respond and help me out here. Thanks.


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## narhay (Feb 28, 2007)

May I suggest drilling the tank? Put your fish, if you have them, in the sump. Get two pieces of glass cut slightly shorter than the water level you want and silicone them into the corner to make a box. Drill two holes on top of each other in the back glass where the box you have made is. The bottom drain is a straight pipe with a valve to control the flow down to the sump (no holes, just solid tubing...it acts like a silent syphon), the top pipe is an emergency drain in case the water level in the box gets too high with a small hole drilled in the cap (search for external durso). It's foolproof, silent and works and looks much better than what you have. The total cost for me was:

Bulkheads $10 each x 2
Glass $20
Plumbing $20
Cement $5
Ball valve $15


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## hidenseek (Nov 13, 2005)

narhay- The whole purpose of building one of these overflows is so one does not have to drill their tanks and waste space in the tank by adding these boxes in the corner. Trust me I've researched drilling my tank and would prefer not to do so. I appreciate the input and suggestion.


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## Mcdaphnia (Dec 16, 2003)

hidenseek said:


> narhay- The whole purpose of building one of these overflows is so one does not have to drill their tanks and waste space in the tank by adding these boxes in the corner. Trust me I've researched drilling my tank and would prefer not to do so. I appreciate the input and suggestion.


For some reason, a drilled tank seems to be at a premium in the saltwater end of the hobby and avoided like the blazes by freshwater aquarists.


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## narhay (Feb 28, 2007)

Agreed. Same with power compacts. They're relatively good technology here but pretty outdated in the SW side of things.


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## boredatwork (Sep 14, 2007)

I should save a copy and paste of my little rant every time I do it. But knowing that I do it from scratch every time should should you how much I care, hahaha. (You can decide if that was a genuine "hahaha" or a sarcastic "hahaha".)

Also, after going through a couple posts today I feel like emotions are running high at the moment. Maybe it is a full moon or something? I just hope I don't get yelled at.



> For some reason, a drilled tank seems to be at a premium in the saltwater end of the hobby and avoided like the blazes by freshwater aquarists.


An excellent observation. I would like to extend it by saying there is a lot to be learned in the freshwater hobby from the saltwater hobby. If you ever spend some time on some of their forums I think most people would agree. In one sense it is kind of a shame. I feel like the freshwater hobby in general is like a second class citizen to the saltwater people. But that's a whole other post for another time.

hidenseek, it is true that many people have implemented this type of overflow. If you do a search on this forum and read through all of the posts related to sumps and overflow, as many people have done, I think you will find that every single one of them is noisy. Here is why.

First, lets define noise. Noise is anything that can be heard. A humm, a gurgle, even the soft purring of water getnly flowing down a PVC tube, etc., they are all noise. Some people manage to justify the noise away as "peaceful" but it is still noise. I always feel the need to clarify that because I have been tricked too many times by the claims of "silence" only to find out the person was either deaf or using some obscure definition of noise.

Second, lets figure out why overflows are noisy. An overflow works by sucking water out of the tank and into the sump. Or is it? Alas a sharp reader would know that is only half of the definition, so lets refine it. An overflow works by sucking water out of the tank and air out of the vent. The complete definition is of utmost importance to understanding the noise. As an experiment, cap the vertical PVC vent on your overflow and see if the overflow works? In an over the tank overflow the air is an essential part. The problem is that the air, an integral part of your overflow, is also the cause of the noise.

This time lets conduct a thought experiment. Think about all of the times you have done a water change using vinyl tubing. (And if you haven't then maybe we need this to be a little more than a thought experiment). You fill the tubing with water and put one end in the tank and one end in the bucket. Once the bucket end of the tubing drops below the waterline of the tank the water is sucked out of the tank and into the bucket. This is an example of siphon. In this scenario there is no air in the vinyl tubing. You will also recall that there is no noise - because there is not air in the tubing.

The air in your overflow is the cause of your noise problem. There are many ingenious solutions out there that will muffle the noise, but they will not make it go away. The reason they cannot make it go away is because they do not remove the air from the drain pipe. In some cases they control how much air is sucked in, and in other cases they simply try to dampen the sound. The only way to make the noise go away is to remove the air from the drain pipe. In your setup this is not possible, as witnessed in our first experiment.

In other words, the setup you have cannot be silent.

Now, if you had a drilled tank or use a skimmer overflow, then you have some options available to you to build a quiet overflow, hence the suggestions.


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## KaiserSousay (Nov 2, 2008)

Just a thought..I still have them on occasion..
On my pretzel, if I plugged off the vent, I went to full siphion in a hurry. A full siphion is totaly silent..if one could rig a solenoid valve, normally open, held closed by the same power your pump runs on. In case of power outage would this not "gurgle" on down to it`s normal shut off position and stop.
Question would be, after power is restored, would it start again as the xcess is pumped back to the tank from the sump???


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## willny1 (Nov 17, 2008)

hidenseek said:


> Well, the flow rate is still real slow so I'm going to have to build another one out of 1 1/2" pvc tomorrow. That should flow a little better I hope. I want to have a high return rate so I can have a spray bar to create a good underwater flow for my loaches. They like that sort of thing. I have two powerheads also so I'll be using those as well. Thanks for all the help. Looks like I have some more reading to do. Even having read that 70 page long thread on MFK.com!!!


1 1/2" may be over kill. 1 inch should be good. But I guess it depends on how much turn over rate you want on your tank. How big is the tank? What type of fish do you keep?


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## avy1219 (Jan 8, 2006)

Glad you found the problem. What i did to help the noise what put a cap on the upper end with a hole drilled into it. That seems to help more then you would think. As far as the tornado effect inside the tank to prohibit that I just cut a " T " shape out of the side of a milk jug and shoved that into the intake. i made the lower half of the " T " a little larger then the inside of the pipe so it would fit tight, and made the upper part of the " T " a half inch or so bigger on each side of the pipe. Seemed to work like a charm....


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## hidenseek (Nov 13, 2005)

avy1219 said:


> Glad you found the problem. What i did to help the noise what put a cap on the upper end with a hole drilled into it. That seems to help more then you would think. As far as the tornado effect inside the tank to prohibit that I just cut a " T " shape out of the side of a milk jug and shoved that into the intake. i made the lower half of the " T " a little larger then the inside of the pipe so it would fit tight, and made the upper part of the " T " a half inch or so bigger on each side of the pipe. Seemed to work like a charm....


I'll have to give that a try also avy1219. Thanks.

I really do appreciate having this discussion with all of you. I know by some of your comments you would rather this whole thing just be disposed of and never mentioned again! To say the least. I agree to a point, but love new innovations that people come up with all the time. The longer we talk and play with these things the more we discover.

Along those lines I would like to share something new I just found out with my pvc overflow. Might not be new to a lot of people, but it's new to me. I was messing around with the outlet into my sump tank by restricting the flow with my finger (insert joke here!). What I came to find out is that by decreasing the outlet diameter I was able to nearly silence the whole device by trapping the air inside the pipes. I'm assuming that's what I was doing anyways because I didn't feel or see any air bubbles.

Now I'm thinking I really need to run out to the Home Depot and get another ball valve for my outlet downpipe, or just shove something into the pipe to replace my finger (insert more sarcastic humor). Just another tip out there that might help some folks out.

Feedback welcome. Thanks.


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## avy1219 (Jan 8, 2006)

hahaha.... I'll save my jokes, but dont you worry I do have some good ones. I did sort of the same thing at one point..... LOL... ok well i guess not the same thing, but I just stuck a 90 elbow on the end of the outlet and aimed it at the sky, so the water had to fill the 90 and flow over the top of it.......... IF that makes any sense...


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## hidenseek (Nov 13, 2005)

avy1219 said:


> hahaha.... I'll save my jokes, but dont you worry I do have some good ones. I did sort of the same thing at one point..... LOL... ok well i guess not the same thing, but I just stuck a 90 elbow on the end of the outlet and aimed it at the sky, so the water had to fill the 90 and flow over the top of it.......... IF that makes any sense...


Sounds like an idea I'll have to try. This would be a good way to find out how much pressure is running through the pipes. I can already see myself cleaning up another mess! I'mma try the ball valve and your ideas tomorrow. All this experimenting and thinking has got my head pounding. Thanks avy1219.


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## hidenseek (Nov 13, 2005)

Good morning everyone. Just thought I would get back on here and share my findings. I stopped off at the home depot today for a new 3/4" pvc ball valve for the pvc overflow. I recently got home and attached the ball valve to the outlet pipe in the sump tank.

Needless to say my predictions were right on!!! The restricted flow caused by the valve traps the air up in the pipes and provides me and my wife with the peaceful humming of the return pump. Not so peaceful actually. Quite annoying if you ask me. Well, not all of the air is trapped in the pipes. There is always going to be some air getting by depending on how you regulate your valve.

I'll take some pictures in a little while and post them up for all the nay sayers to see. Hope everyone already knows this modification, but to those that do not I'm happy to help anyone out there with a problematic pvc overflow.

Thanks for lookin.


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## boredatwork (Sep 14, 2007)

That is a known modification. In fact, this is the only modification that will make a sump quiet. However, with that setup it is usually recommended to have an emergency drain pipe as well.

Basically what you did it stop the air from going in the pipe which means no noise. Now the problem is reliability.

If you have a lot of time on your hands you can read this:

http://www.reefcentral.com/forums/showt ... genumber=1

If you read through the whole thing, when you get to the end, you will see a discussion on why, even with an emergency drain, this type of setup is potentially dangerous for over-the-tank overflows.

On the other hand some people do use it without an emergency drain and claim to have no problems, but in my opinion that can be risky.

As for your noisy pump, put a sponge underneath it and that should quiet it down.


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## hidenseek (Nov 13, 2005)

**** got me again. Guess I'm still a bit behind the power curve so to say. I'll have to check out that thread in a bit. I'm painting my kitchen so fish tank is on the back burner at the moment. Thanks bored!


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## boredatwork (Sep 14, 2007)

Its not about "getting" you. I will try to explain this nicely, since this could come off seeming mean.

I do not consider myself very smart or very experienced in this hobby. But if you frequent this forum for a decent amount of time, and your best friend is the search function, you will notice that of the thousands of posts it seems like there are about 15-20 unique questions that are always asked. Sumps and overflows is probably one of the top 5 questions.

When overflow questions are posted I bet you a lot of people on this forum can pretty much predict exactly how the discussion will go. In that sense its almost "been there, done that". In fact, if that was not the case this forum would not be very useful. We would all just be re-inventing the wheel, and while that may be fun, trust me, it wastes a lot of money and that is not fun.

From that perspective, I have spent a lot of time and money trying all of the various overflow techniques and gadgets out there. It cost me a lot of money. In the end I feel like I came an understanding of the problem behind the noise. The knowledge is the most important part. Now that I understand why a sump is noisy, I know how to fix it. My intent in participating on this forum is to do two things, prevent people from wasting as much money as I did, and to try to impart some amount of knowledge regarding the advice I give.


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## hidenseek (Nov 13, 2005)

I know where you're coming from. Trust I didn't take anything you said as negative towards me. I know it's all constructive advice to help me out, and believe me I do appreciate the help.

I do use the search function quite often, but after reading a couple posts and don't see a good answer I move on. After going through twenty or so threads that don't answer my question, that's when I post a new thread. Thanks for taking the time to answer the same threads over and over again.

As for that thread link you posted. What I'm taking from the few posts I read is that the emergency line is for if and when the main overflow loses suction. Kind of like a back up so the main tank doesn't overfill. I can see where this can be helpful. When testing if my overflow would regain suction on its own I found it took it a while to get back up to it's full potential. However, I think I have this under control. "Think" being the operative word. I'm actually planning on using two sump tank to control water level in the main tank and act as Q tanks and hospital tanks. I really don't know my thinking behind this idea yet, but it's just another thought I have swirling around this head of mine. Two sumps to distribute the overall water volume. Hopefully experiments will prove effective.

Thanks again.


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## boredatwork (Sep 14, 2007)

The emergency drain is not used for a loss of suction emergency. Most reefers do not use over the tank overflows. As in that example they used a drilled tank, which do not rely on suction, so that could not be the reason.

The emergency drain is due to the fact that a valve on the drainpipe is used to set the drain flow rate so that air is not sucked into the drainpipe. In normal operation this will increase the theoretical threshold of the drains maximum flow rate. However, the source of the problem is that when you dial in the ball valve, you are assuming a fixed flow rate out of the return from the sump pump. There are many potential variables associated with both the flow rate of the pump and the flow rate of the drain. Ideally you are assuming that you have set the ball vale on the drain to match the sump pump flow rate to the drain flow rate. But again, if either of those two values were to change, you could run into a flood.

That is the purpose of the emergency drain.

But, like i said before, some people claim it is not necessary. However, of the many people that have used the valve on the drain line, there are a significant number of them that have experienced problems, so to me, its worth including.

In your case it is simply adding another PVC overflow. Adjust the height of the drain in the tank to be a little bit above the water line, and do not put a ball valve on the drain into the sump. Of course, make sure that the overflow is primed.

Also, I want to be clear to everyone who comes across this thread, using this method with an over the tank overflow is potentially risky. Risky meaning potential for flooding.


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## hidenseek (Nov 13, 2005)

Oh cool. I get it now. That does seem to make sense. However, at the time being the amount of water in my sump tank would not overflow my main tank so no problem there. Thanks for clarifying that one.


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