# Diy pvc overflow retrofit?



## BOTIA (Dec 23, 2003)

I'm thinking of adding a sump to my canister filtered tank.
Here are my reasons
1) Constant water level ))

2) Additional water movement in the tank

3) Heater in sump (less equipment in tank)

4) additional filtration (last because I don't really need it)

5) put my uv on the sump line to let my canister run faster

I plan on using either a 10 gallon tank or a rubbermaid type bin. I calculated me evaporation loss at 4.5 gallon/week btw so a 10 gallon should work.
I also plan on a well sealed lid on the sump and the water inflow pie would be right on the bottom of the sump so no splashing and minimal co2 loss.

The spray bar is a new idea (Ithink) I plan on drilling a long 1/2 hole into a piece of mopani wood and then drilling out let holes into that 1/2 hole. So it would be a wood spray bar and basicly invisible. It would be fed via under gravel 1/2 inner diameter pipe .

Whacha Think Guys/Gals
Botia
Here is a pic of a diy pvc overlflow from the net


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## SCMurphy (Oct 21, 2003)

I use this style overflow on my sump set ups. 


Use as Tall a tank for the sump as you can reasonably fit under the stand.
Use a ball valve on the pump's outflow to balance the system, the pump will think it has more head to fight.
Use 1 inch PVC minimum, fit all the pieces together and check the flow rate BEFORE you glue any of it up. I've found I need to use at least 2 overflows like this to get enough water to the sump to have a reasonable flow rate.
I made strainers from clear PVC for in the tank, drilled about 200 small holes in them to reduce the suction on any one hole.
Have the overflow pipe go all the way into the sump and underwater, it reduces CO2 loss.
Put a section of pipe that rises ABOVE the rim of the tank in the open section of the T and put a cap on it with a 1/8 inch hole drilled in it, this kills the noise of the overflow and allows you to make a quick siphon by covering the hole (assuming that you did 5) which ensures that any bubbles that may have gathered in the pipe are pulled out.
The horizontal pipe to the T determines the level that the tank will drop to if the pump shuts off, you need this to be far enough below the water level in the tank that you get a good flow, but not so low that you pull more water than your sump can handle if the power goes off. Be conservative on this to start and lower it when you get the hang of it.
When you get the flow and tank level balanced, turn off the pump, wait for the flow of water to stop, check the sump. I fill the sump up to about an inch below the top at this point, margin of error. DON"T fill the sump up while the pump is running, you will have too much water in the system.

The return you describe will need a check valve on it to keep it from siphoning out your tank if the power goes off.


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## albinooscar (Jan 25, 2005)

Hey guys. 
Is there any particular dimension on the up-down portion before the tee of this overflow?


Ron


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## GulfCoastAquarian (Jul 30, 2002)

In order to break the siphon, I'd think you would want at least 4"-6" from the opening to the bottom of the U-section.


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## albinooscar (Jan 25, 2005)

Check this bad boy out!

http://reefcentral.com/forums/showthread.php?s=&threadid=503664 roud: :drool: 

Ron


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## SCMurphy (Oct 21, 2003)

albinooscar said:


> Check this bad boy out!
> 
> http://reefcentral.com/forums/showthread.php?s=&threadid=503664 roud: :drool:
> 
> Ron


That's a lot of PVC in the tank! I'm avoiding surface skimming to keep more CO2 in the system, and the level control section is outside of the tank. I do like the check valve system that he put on the upper elbows, I hadn't thought of that.



albinooscar said:


> Hey guys.
> Is there any particular dimension on the up-down portion before the tee of this overflow?
> 
> Ron


The difference in the two external uprights is around 2 inches, but this can change based on the size of your sump and aquarium. You need it low enough that you get enough draw, but not so low that you overfill your sump.
I like I said before, be conservative and trim down, dry fit, and test run.


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## SCMurphy (Oct 21, 2003)

GulfCoastAquarian said:


> In order to break the siphon, I'd think you would want at least 4"-6" from the opening to the bottom of the U-section.


Actually, this is designed to stop flow but not break the siphon. When the water level in the tank drops below the upper vertical to the half open T the flow stops but the siphon in the rest of the pipe is maintained. So, after a power outage the overflow is back in business without interention or mess. 

It's nice to turn off the pump, change the water in the sump 100% and then start the pump back up. I get a 25% water change that way.


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## GulfCoastAquarian (Jul 30, 2002)

SCMurphy said:


> Actually, this is designed to stop flow but not break the siphon. When the water level in the tank drops below the upper vertical to the half open T the flow stops but the siphon in the rest of the pipe is maintained. So, after a power outage the overflow is back in business without interention or mess.
> 
> It's nice to turn off the pump, change the water in the sump 100% and then start the pump back up. I get a 25% water change that way.


 Well, right, it will start right back up, but what I was saying is that air will enter the upper horizontal spar and stop the flow of water. When the pump starts up again, the water level in the tank rises and starts to fill that horizontal spar, and re-forms the siphon. So in this effect, the siphon is broken, but automatically restored.
Haha, this is impossible to describe.


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## SCMurphy (Oct 21, 2003)

GulfCoastAquarian said:


> Well, right, it will start right back up, but what I was saying is that air will enter the upper horizontal spar and stop the flow of water. When the pump starts up again, the water level in the tank rises and starts to fill that horizontal spar, and re-forms the siphon. So in this effect, the siphon is broken, but automatically restored.
> Haha, this is impossible to describe.


Sam, it's always fun to mince semantics with a nice guy. I figure we know what each other is saying, we are just trying to clear up the language.  

So, just for clarity, I would have to say that if the siphon breaks then the unit won't work when power is restored. The unit preserves the siphon, the water filled pipe over the edge of the tank. I heard someone call it a 'constant level siphon' but I don't know who to give that credit to. Lower the tank level and the flow stops, the siphon stays, and the world is good. roud:


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## GulfCoastAquarian (Jul 30, 2002)

A picture is worth a thousand words. But am I understanding it correctly?


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## SCMurphy (Oct 21, 2003)

GulfCoastAquarian said:


> A picture is worth a thousand words. But am I understanding it correctly?


No, but you are *REALLY *close. roud: 

When the flow stops, the long pipe to the sump is empty. :wink:


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## GulfCoastAquarian (Jul 30, 2002)

Ah right, I guess there would have to be an insane amount of surface tension to retain the water in the column. I corrected the image. 
This sure is a clever device. I'm actually trying to figure out a way I could use it. Just to give it a try, haha.


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## BOTIA (Dec 23, 2003)

*clever*

Sure wish I'd thought of it..
I found the design at the american killifish associations
website.
I going to do it for sure on my 15 tall first then I'll give the "70" a go.
Constant water level is just to awesome a thing to pass up.
The other cool thing is I'm going to feed the output into my ugf to make it a sump driven rugf! Not to mention all the increased water volume , so many plus's to this...

Ps You don't need a check flow valve on the pump apparently they occasionally fail so the better idea is to drill a 1/16 hole at the water line level on the return pipe inside the tank. That way siphon is broken the second the pump stops and maybe only a little extra water re enters the sump.
Botia


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## grungefreek (Oct 9, 2003)

Im also thinking of putting this design overflow on my new 30gal tank. What im going to do instead of having the ugly PVC intake inside the tank, is attach some thick, clear hosing to the elbow that goes over the tank edge. That way the intake tube is less noticeable. Clear acrylic would be better, but the tubing can be attached to the wall by suction cups if need be. I would also do the same for the hose going into the sump, bit more flexibility never hurts. roud:


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## BlueRam (Sep 21, 2004)

BOTIA said:


> Sure wish I'd thought of it..
> I found the design at the american killifish associations
> website.


Botia:

We have a killi nut in our area who is using a derivative of the above. I would like to place it in context if I may. He is keeping/breeding northos in 25 2.5 gal open top AGA's. Each one has a heater/drip emitter/overflow for the express reason of doing water changes. Killies release chemicals that stunt growth so it is necessary to do frequent water changes. For this reason the system is not recalculating in that water only passes through once (from fresh bucket to used bucket. These water changes are also infrequent. I think he is doing ~30 gal a week. He is working on building an automated system. So in this context any overflow for a killi tank must be cheap (you need many) and quick to remove as tanks are changed out all the time. Noise/flow rate is not a problem.

As grungefreek suggested, he is using clear aquarium tubing to make the bend. So the PVC part is a 'T' with the tube in the up side, the return on the T side, and a cap on the down side. If there are fry in the tank he places an air stone over the tube. To remove a tank he pulls the tube and stops the drip emitter. Very clever for so many tanks. For your tanks you might want to be a little more conventional. It will work for the 15 but for the 70 you might want to look at an add on box. They are not so expensive (for one) and are built to handle constant/more flow with less noise. Take a look at this tread for example:

http://www.plantedtank.net/forums/showthread.php?t=12568


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## grungefreek (Oct 9, 2003)

In that top pic, see how the water level in the tank is a good 3-4 inches below the rim, can u have the water level in the tank 1 inch below the rim and still have good water flow? I like my tanks to be as full as possible, usually 1/2-1 inch before overflowing. Prolly not the best idea tho in the case of running a sump. But to adjust the height of water in the tank, do u just make the horizontal piece on the T closer to the top of the tank?


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## Hop (Mar 27, 2004)

With running a sump you just have to place a baffle in the sump where the pump or intake for the pump is. You then make this baffle area contain less water volume than your tank can hold. This way if the overflow stops for some reason you only have a small fraction of the sumps volume pouring on the top.. this stops the risk of ye ol' flood.


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## SCMurphy (Oct 21, 2003)

grungefreek said:


> In that top pic, see how the water level in the tank is a good 3-4 inches below the rim, can u have the water level in the tank 1 inch below the rim and still have good water flow? I like my tanks to be as full as possible, usually 1/2-1 inch before overflowing. Prolly not the best idea tho in the case of running a sump. But to adjust the height of water in the tank, do u just make the horizontal piece on the T closer to the top of the tank?


No, you need to adjust the horizontal pipe to get the best outflow without overflowing your sump during a power outage. To adjust the level in the tank put a ball valve on the return line from the pump and get the pump balanced with the outflow so that the water always stays above the trim line. If my tanks were rimless I could easily get the water to hover within a centimeter of the top of the tank. If you try to adjust the UPPER level of the water in the tank with the horizontal pipe you CAN'T get enough flow through the overflow to effectively operate the sump. I've got them in action on two tanks, I've played this through.

The clear PVC pipe I drilled hundereds of holes in to make strainers has enough surface area that I'm not going to loose outflow from anything that is available in the tank, even a large leaf from a crypt. The flow through each individual hole in that pipe is so small that stuff just doesn't stick to the pipe. 

I didn't glue the strainers into the elbow so I can remove them and occassionally clean out any 'growth' in the pipe. The interesting thing I discovered the last time I cleaned them was the build up of mulm in the cap at the bottom of the pipe.



BlueRam said:


> For your tanks you might want to be a little more conventional. It will work for the 15 but for the 70 you might want to look at an add on box. They are not so expensive (for one) and are built to handle constant/more flow with less noise.


If you use 1-inch or greater pipe you can easily build an overflow that can accomidate larger flows. The reason I didn't want a box is I didn't want to skim the surface and promote CO2 loss. 

The cap with the hole drilled in it that I described above is borrowed from the Durso Standpipe, it completely muffles the overflow sound. Another thing you can do is have the last section of pipe be soft tubing, the annoying sound is created by the resonance of the water flowing through the hard PVC pipe.


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## grungefreek (Oct 9, 2003)

> If you try to adjust the UPPER level of the water in the tank with the horizontal pipe you CAN'T get enough flow through the overflow to effectively operate the sump. I've got them in action on two tanks, I've played this through.


what volume of flow are u getting thru each of these overflows? Mine will prolly be on a 30gal, would one be sufficient? And how do u know what size pump to get? I guess it doesnt matter cause the overflow only works if there is water being pumped back into the tank. But u would need a bigger pump to have water levels to the rim of the tank using the ball valve to control flows wouldnt u?


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## SCMurphy (Oct 21, 2003)

Yes it depends on the pump you are using, it does have to be able to handle flows a little larger than you get through the overflow or you just maintain the maximum level dictated by the overflow. I am using a Quietone 4000 on my 75, I'm looking for a smaller pump for my 56, you certainly won't need something that large on a 30 and one overflow should be plenty. 

I really don't know how much flow I'm getting, just enough to make the Cyprus heleferi wave in the current.


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## BOTIA (Dec 23, 2003)

*a few things.*

Just to get this clear.
1) So the level is not dictated by the "T" it is dictated by pump balancing?
2) The lowest level is dictated by the horizontal "T" OR if using a vertical skimmer tube it would be the top of the skimmer tube. 
3) For a 70 gallon I would probably need one with two 1 inch overflows?
4) What is the best way to prime the system ? and are check valves that much better

Any other tips would be appreciated
Thanks Botia


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## grungefreek (Oct 9, 2003)

I am using a Quietone 4000 on my 75, I'm looking for a smaller pump for my 56, you certainly won't need something that large on a 30 and one overflow should be plenty. [/QUOTE]
I have a 2000LPH powerhead. Would that be a good pump for a 30gal?


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## grungefreek (Oct 9, 2003)

I am using a Quietone 4000 on my 75, I'm looking for a smaller pump for my 56, you certainly won't need something that large on a 30 and one overflow should be plenty. [/QUOTE]
I have a 2000LPH powerhead. Would that be a good pump for a 30gal?

Botia
1. I believe it is the pump balancing that determines water height
2. Yes dictated by the horizontal T section. Dont know what u mean By "vertical skimmer tube" If u mean u have the inlet facing upwards, and the water is drained to that inlet, well i dont think it would restart itself
3. So SC murphy says
4. I think u just suck on that T Piece to draw the water up.

Sure SC murphy will have better answers than me


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## BOTIA (Dec 23, 2003)

*Sc murphy ?'s*

How many and what diameter are your overflows on your 75?
Also do you know what gph your quite one 4000 is at the head you are at?
I have a mag drive 500 I was thinking of using for my 70 .
I am like you in that It will be only for constant water level , heating and probably plumb my uv throught it as well. In the sump I will only have floss.
I am stoked I got the 15 gallon one setup in test phase it is very cool.
Botia


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## SCMurphy (Oct 21, 2003)

The pump balancing determines the UPPER water level, the horizontal pipe to the open T sets the lower water level. 

The vertical skimmer tube is part of the design on one of the reef forums, I don't use that design. 

I am using 1-inch PVC on my overflows. 

My pump has an output of about 750 gallons per hour at 4 feet of head and I have the ball valve cut back about half with 2 of the overflows setup. If I add one more to the system I can open it up to about 85 percent, so one of my current overflows is underpreforming, which means that I didn't set the lower water level far enough down on it.

I don't have the check valves on my overflows, with the lower end in the sump I do like grungefreak says, I connect a PVC pipe to the upper part of the T and suck some air out of the system. The overflow starts really fast. Once it is running with the 'muffler' cap in place I can make a full siphon by covering the hole and waiting a minute. I do this every now and again to ensure I don't have a bubble build up in the pipes. I doubt I get one though with the water moving at the rate it does normally.
=====

Botia,

You keep listing different things you are going to attach your sump to, some of them won't bother anything, some raise additional problems that you need to account for before you actually let this thing run. On their own these overflows and a sump return are pretty stable systems and I haven't had a problem with them. I can't vouch for some of the ideas you have, I can only wish you luck.


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## SCMurphy (Oct 21, 2003)

GulfCoastAquarian said:


> Ah right, I guess there would have to be an insane amount of surface tension to retain the water in the column. I corrected the image.
> This sure is a clever device. I'm actually trying to figure out a way I could use it. Just to give it a try, haha.


Sam,

I actually have an extra one I set up to use for water changes on my other tanks. I get it running on a tank, then I start little more than a trickle of water flowing to the tank, and give it a bit of time. Later I take it off the tank and let the tank fill up to the right level before stopping the water. 

The outflow either goes to a water disposal unit (no need to flush :wink: ) or outside to the garden.


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## BOTIA (Dec 23, 2003)

*Well I did one...*

Well 
I built the overflow for my 15 Gallon tall tank today. I know kinda silly to have a sump on a 15 but It's nice to have the heater and powerhead and AC Mini Hob out of there. The sump just is actually just a pail will a ac500 sponge wedge across the inside with outflow on one side and the ac4000 on the other. 
I used some extra ehiem 1/2 inner diameter tubing for the outflow and hooked into my ugf tube to make it rugf. 
My co2 offgassing is way down and I have seen some pearling already which has never happened before.
The tank is hazy however , I'm guessing it's because of switching the flow to rugf. 
The overflow is made with 3/4 pvc and the ball valve is about 70 % slowed as the ac4000 is 369 gph but has alot of power compared to ther less torquey powerheads.
I might pick up a small via aqua pump eventually.
It was a little nerve wracking balancing the pump and overflow but it was worth it.
The is tank btw has a really nice solid oak cabinet and a matching Diy hood I made for it since it resides in my 18 month old daughters room. The tank was setup for her 7 months before she was born.
I also have built one overflow for 70 out of 1 inch pvc. On this tank is the same just for heating and constant water level. I have a mag 500 for this tank to use we'll see if the 1 inch can handle it at 3.5 ft of head =ing about 300gph. My one issue is that the cabinet is running out of room with 6 2L yeast generators, a uv , a canister filter and all my test kits and ferts algae scrubs etc.
Botia


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## FeatherfinFan (Feb 3, 2005)

Thanks for the great tips & photos, I'm building a 100-120 gallon acrylic planed tank in the coming weeks and was going to utilize an in-tank durso but after seeing these tips I think I'll just keep the pipes outside and use two 1" pipes as shown.
Sean, you made the following quote on another thread:


> Then using a ball valve on the return line you can limit back the pump you use (I have a QuietOne 4000) to the 'balance point' where the in and outflows are equal. The ball valve acts like an increase in the head of the return which safely limits how much water the pump lifts.


I'm trying to understand this, wouldn't the flow going from the return pumps equal the flow getting siphoned to the sump regardless of flow rate? Or is this installed as insurance in case you have too much pump for your siphon capacity?


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## SCMurphy (Oct 21, 2003)

FeatherfinFan said:


> I'm trying to understand this, wouldn't the flow going from the return pumps equal the flow getting siphoned to the sump regardless of flow rate? Or is this installed as insurance in case you have too much pump for your siphon capacity?


The pump is capable of about 700 gpm at 4 feet of head, the overflows are drawing about 300 gpm (very rough estimate) so I had to either get a smaller pump or cut back on the flow of the ones I have. Putting a ballvalve on the pump's outflow sends the same 'resistance' as increasing the head would. It also allowed me to set the water level in the tank.

For a 100 to 120 gallon tank I'd either increase the diameter of the pipe used or use more overflows. You can also modify the design a bit, I have one overflow set up with 2 open T's which draws about 1.7 times as much water as an overflow with one open T. I was hoping for a 2x increase in draw but it didn't quite happen.


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## FeatherfinFan (Feb 3, 2005)

Thanks for the clarification Sean, would you think (2) 1" overflow units would be sufficient for a 100-120 (w/ a 35 gallon sump) and I'm shooting for about 500GPH thru the system. I could use thin walled PVC for the overflows to help a bit w/ the flow.


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## SCMurphy (Oct 21, 2003)

I think if you use solely 1-inch pipe you need more than 2 overflows. You might be able to use 1-inch in the tank for the strainer but make the rest of the piping 1.5 inch to try to increase the draw. I have wanted to try this to see if it would pull more water but the 1-inch to 1.5 or 2-inch fittings are hard to come by at the local stores, amazingly enough, and I haven't tried to order some online yet.


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## FeatherfinFan (Feb 3, 2005)

Thanks, I may try two 1.5 inchers then, always better to have excess flow capacity than not enough. BTW, what's the best way to get the siphon started, just manual suction on the opened "up-tube"(like siphoning gas, LOL) or is there a more sophisticated way?


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## SCMurphy (Oct 21, 2003)

I suppose there is a sophisticated way but I seem to be stuck in the past and use the manual method. :redface:


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## FeatherfinFan (Feb 3, 2005)

Sean, it's been awhile but I just thought I'd share a couple things and ask another question. I just tested one of my overflow tubes and it's draining at a rate of 4GPM or 240GPH. I used schedule 200 1" PVC so it's about .200 of an inch larger in ID than schedule 40, so I'm guessing the flow through 1" schedule 40 PVC would be in the 200GPH range. You mentioned getting about 1.7x the flow through your pipes when going w/ a twin "T" setup. Just curious how you set this up as I'm also going w/ a QuietOne4000 and really don't want more than two overflow tubes in my tank. Also, it sure is quiet when using the drilled cap, thanks for all the tips


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## SCMurphy (Oct 21, 2003)

Basic design drawing with dual lines to sump from one intake pipe.
e = elbow
t = T connector
I have the unit folded up on itself so it doesn't take up this much space on the back of the tank. I spread it out in the illustration to try to make it clear.


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## FeatherfinFan (Feb 3, 2005)

Thanks for the details Sean, If I make all the horizontal connectors as short as possible I may be able to accomodate it OK, and having 1.7x the normal flow will solve my flowrate situation. 
A couple other questions if you don't mind~
How do you like the QuietOne4000, is it pretty quiet, compared to say a Mag7?
Also, how far down the in-tank pipe do you start your drilled holes? I'm going to use just the PVC w/ a cap and drill as you did, but I'll be hiding the pipe w/ black silicone rather than the clear PVC. How long is your in-tank pipe (total length) as I'm hoping I can get by w/ about 8-10 inches w/ the last 4" drilled out.


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## SCMurphy (Oct 21, 2003)

If you fold it up it takes less space, before you glue it up try changing the configuration. Of course if you don't have room for a large item behind the tank, making it wide and flat like in the illustration will work.

I have never heard a Mag pump in operation so I can't compare.

I drilled the holes on the bottom third, the pipes are around 10 to 12 inches long in the tank.


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## jgc (Jul 6, 2005)

Darn just found this and realized I had reinvented the wheel this morning (including the folding idea).

Great idea. It might just end up on my Daughters Nano. Initally I had not planned on using the T but just another U. I do not think this will be would have been an issue either way, but with the T It will be easier to prime.

The one I am planning will be palm sized though..., folded into a Diamond shape - one pipe on the inside, and a triangle of 3 on the outside.

Oh, harbor freight has a tabletop pump onsale for Father's day for about $6 - so this will be a cheep nano project if I do it.
---
Thought about it more, and will omit the T. I can not see how the T will help me eliminate the air buble that will form in the first U. The T will get the syphon started, but will leave air in the U which will/might cut down on the capacity of the overflow. The unit I am planning will be small enough to submerge to prime.


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## SCMurphy (Oct 21, 2003)

The open T is what makes the unit 'release' when the power goes out. If you put a U there you will have a siphon that will continue to draw water until the level in the tank hits the highest opening on the intake pipe. With the T the siphon is maintained in the first half of the pipe but flow to the sump stops until the pump in the sump starts sending water up to the tank again.

*****

On a side note, I got some black pvc to try out for the strainer. If you paint the back of your tanks black, the black pvc absolutely dissappears against it. I'm going to switch all my strainers over to the black pvc, on my black backed tanks, as soon as I have time.


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## hazeen (May 21, 2006)

*Drilling the Glass*

Well .. both sites are really interested ..:thumbsup: 
I do have drill, the Glass is not tempered .. there is a risk ..a will buy the bit ..and make a hole as directed in the site ..
also..the PVC overflow as mentioned is much easier to make a hole..! but i think i will go ahead with a drilling the glass..:icon_eek: 

i will let u know the final result with this.. many thanks again and again


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## hazeen (May 21, 2006)

sorry wrong post,but seems related to same subject


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## Hoppy (Dec 24, 2005)

hazeen said:


> Well .. both sites are really interested ..:thumbsup:
> I do have drill, the Glass is not tempered .. there is a risk ..a will buy the bit ..and make a hole as directed in the site ..
> also..the PVC overflow as mentioned is much easier to make a hole..! but i think i will go ahead with a drilling the glass..:icon_eek:
> 
> i will let u know the final result with this.. many thanks again and again


I know this was supposed to be in the thread about your problems drilling your big tank. When you do this, please take some pictures and let us see how it works. It takes a lot of courage to drill a glass tank!


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## Naja002 (Oct 12, 2005)

> The open T is what makes the unit 'release' when the power goes out.


Does anyone know if the size of the T opening effects the flow-rate?

I built one of these with 1" sch. 40 pvc and it works, but I am wondering if my flow-rate is restricted by the T-opening: I capped the T and drilled an hole, inserted an aquarium airline connector and about 1' of airline tubing. The system works and the sound is muffled--but is it being restricted by this small opening? Would another hole help?

At full siphon-- it draws a lot of water......

TIA


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## SCMurphy (Oct 21, 2003)

Do you mean the inside of the T connector, or the size of the hole drilled in the cap to muffle the system? I tried drilling a smaller hole once, it can tend to pull more water as the hole can be small enough to form a partial siphon. I use a 1/8 inch drill bit for the hole.


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## Naja002 (Oct 12, 2005)

I mean the hole drilled into the cap. I drilled a hole big enough to insert one of the airline "Couplings" like this:













> I tried drilling a smaller hole once, it can tend to pull more water as the hole can be small enough to form a partial siphon. I use a 1/8 inch drill bit for the hole.



Got me thinking.......I have some of the cheapo airline control valves: I'll put one on that airline and see what effect I get from closing it down some. Not completely, but see if limiting the air-intake will increase flow, yet still break the siphon when power to the pump is gone......hmmmmmm

Any thoughts?


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## SCMurphy (Oct 21, 2003)

Naja002 said:


> Any thoughts?


Give it a shot. roud:


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## Naja002 (Oct 12, 2005)

Ok. 1) It Works, 2) there's a possible pitfall that I cannot test ATM. I have a Quietone 1200 pump that is only 296pgh operating with 4' of head through 1" pvc (~195gph).

Basically, I can create a Full-siphon that will break with a power failure--that's not a problem. The problem is: it takes about 5 minutes after the power resumes for the full-siphon to resume. So, I am _*assuming*_ at this point that: inbetween power-return and full siphon--the tank would begin to overflow. Without a bigger pump there is no way for me to check this out. I want, need and plan on getting a bigger pump, but that's no help atm.

What happens for me is a "Tidal effect". The power returns and the tank begins to fill. As it does the siphon--very slowly--begins to get stronger and stronger until a full-siphon is achieved (~5 mins). Then the siphon is so strong that the pump cannot keep up and the water level in the tank decreases to the low-point set by the pvc. Then the siphon stops and the cycle is repeated as the tank begins to fill again.

I have a ball-valve on my overflow, so I will try restricting the overflow and see how that works, and report back in a little while......


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## SCMurphy (Oct 21, 2003)

OK bud, just keep a mop handy. :biggrin:


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## Naja002 (Oct 12, 2005)

I cannot say what the outcome would be with a bigger pump, but this is what I've found:

I was running the system with the overflow wide open and the pump restricted--Now its reverse. There _*Is*_ a noticeable increase in flow, and with a larger pump the increase would be remarkable for my system.

I turned off the pump and allowed things to settle until flow had completely stopped. When I turned the pump back on the water level rose until I could just barely see the interior rim lip. It stayed there for a few minutes and then the level began to drop very slowly. What I noticed after watching for a while was a very small tidal effect--1/2" or less. So, with a little more tweaking this could probably be eliminated.

The setting on the air valve for maximum effect is not hard to locate. But I did find that when I closed the airline valve only 1/4-turn more--the siphon did not break---So, the setting is important and needs to be tested before faith is put into it. The siphon is so full that the overflow bubbles the intake-air out of the bottom end--its continuous, not temporary.

The hole inside the airline valve/coupling is 3/32(=6/64)-7/64".

I will have to test this potential power-on overflow problem when I get a bigger pump. Things _*Appear*_ to be ok, but who knows....:hihi:

At any rate, my flow is now faster because my pump is wide open and the overflow is restricted.....roud:


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