diy overflow box

[hermit]

custom make the overflow box for weishun who is doing his new 3 footer setup...............

works perfectly well...............

siphon rate is high

BUT............................................

WATER KEEP SPLASHING ON TO THE FLOOR when starting the siphonning............

lucky is fresh water............

anybody can teach how how to start the water siphon..........

as this is the first time playing with tat toy..........

[hermit]

another pic

[hermit]

side pic

[hermit]

front overflow pic

[typrobin]

instead of using a single siphoning pipe, u should have added a second one...to increase the siphoning rate, i would definitely prefer to have a higher flowrate...

if not, instead of 25mm pipes, u should have used 40mm ones....

[hermit]

yah bro tats wat i tried out also..............

using 2 pcs 20mm and 1 pcs 25mm..................

running on return pump 2500 l/h

[weishun]

Hmmm so far the overflow works fine, but for long term usage, i am worried bout my water level. Water level is abit too high to the brim liao. So how? Who can give us some tips, we spent almost half day playing with water in my balcony leh.. haha.

[nim75sg]

From the pic it seems that both the interior box and the exterior box are of the same height.

IMO, increase the height of the exterior box, have another 25mm piping (using a 2500 L/H pum); and install a valve to the both pipings going to the sump. Or use two overflow box.

Alternatively you can using a lower flowrate pump without drilling another return outlet or using 2 of this units.

1) Before starting to siphon, make sure the valve is closed.

2) Open the valve to start siphon and power the return pump at the same time

My 2 cts ..

[thc]

Mod the inner box into a adjustable box. You can control the water level and i believe also the flow rate. Check this out for an idea.

[hermit]

From the pic it seems that both the interior box and the exterior box are of the same height.

IMO, increase the height of the exterior box, have another 25mm piping (using a 2500 L/H pum); and install a valve to the both pipings going to the sump. Or use two overflow box.

Alternatively you can using a lower flowrate pump without drilling another return outlet or using 2 of this units.

1) Before starting to siphon, make sure the valve is closed.

2) Open the valve to start siphon and power the return pump at the same time

My 2 cts ..

yah bro......................

actually the external box and the internal box are not the same height............

to make the siphon works more efficient the length of downward fall must be higher than the upward suction of the siphon pipe................

because u take the

true volume flowrate of siphon pipe in an overflow box =

difference in their water level x gravitational pull x cross area of piping

- frictional loss in pipe(take it as 0)

then you will actually find out that the longer the difference in length the better of the siphon..............

b cos more water is being draw out at a high flow rate mah......................

for weishun case i have actually under calculated tat by right the overflow box should be 3inch(made at 2inch) below frm the top of the tank................

pump too strong for the overflow box...........

luckily tat i have put in the valve to control the inlet and outlet rate................

found out also tat the true flow rate(Vr) at the return pipe nozzle must be equal to the siphonning flow rate(Vs) of the overflow box then the thing will works perfectly in an ideal condition...........................

but if Vr is greater than Vs the overflow box siphon pipe cant cope or get rid wif the high volume of the water into its box and thus overflow, causes FLOOD..........

likewise IF Vr is less than Vs, in layman term tat the siphon i can say the suction is so fast tat it will suck all water off b4 the Vr can give in more water for the cycle

to continue........................so at the end draw in air and so stop the siphon..............end FLOOD again..................

my wise advice to reefer is ????????????????

be careful of using overflow boxes.....

but still want to hear frm ppl who are good in handling wif overflow box.......

[Navyblue]

Hi Weishun,

IMHO, as the Typrobin said the external box should be higher than the water level. If not, if something were to stuck downflow, or downflow valve is closed (if you have one), water will overflow from the box.

If the external box is higher than the water level, when the above scenario happens it will just stop siphoning when the water level in main tank and box become the same.

I agree with the above suggestion also to have a dual siphon tube in case one failed you will have flood unless you have some safety measures at the intake of the pump.

One problem I see with the design is, the "U tube" for siphoning, the length on the outside should be higher than the one inside, or not once you off the main pump, the siphon will be broken you you need to restart the siphon. That is why you say when it "sucked too fast" you will have flood. If you restrict the flow so to let it not suck to fast, as Weishun worried, it will one day flood, as the flow sometimes get inconsistent.

[Navyblue]

You should allow siphon box to have its maximum flowrate without restriction. The pump flow should be the limiting flow rate in this case.

Siphon box should break its siphon under no circumstances unless air trapped in siphon tube. Thus under normal circumstances it will not break siphon and will restart automatically everytime.

[FuEl]

The U-tube should be the same height on both sides. Being longer on either side will give you problems. If the external tube is longer, if your return pump stops, the water in the inner box will continue siphoning into the external box until the siphon breaks. The external tube should always be submerged in water if not the siphon will not be able to restart by itself. Hope you can get what I am trying to point out...

[hermit]

sure is it the case......................

to have the u tube both the same length?

[FuEl]

According to the overflow box I am using that's how it is.. siphon never breaks.

[hermit]

thks bro............

do u have any pic to show me how ur overflow box working????

thanks alot bro

[hermit]

Hi Weishun,

IMHO, as the Typrobin said the external box should be higher than the water level. If not, if something were to stuck downflow, or downflow valve is closed (if you have one), water will overflow from the box.

If the external box is higher than the water level, when the above scenario happens it will just stop siphoning when the water level in main tank and box become the same.

I agree with the above suggestion also to have a dual siphon tube in case one failed you will have flood unless you have some safety measures at the intake of the pump.

One problem I see with the design is, the "U tube" for siphoning, the length on the outside should be higher than the one inside, or not once you off the main pump, the siphon will be broken you you need to restart the siphon. That is why you say when it "sucked too fast" you will have flood. If you restrict the flow so to let it not suck to fast, as Weishun worried, it will one day flood, as the flow sometimes get inconsistent.

"IMHO, as the Typrobin said the external box should be higher than the water level. If not, if something were to stuck downflow, or downflow valve is closed (if you have one), water will overflow from the box.

If the external box is higher than the water level, when the above scenario happens it will just stop siphoning when the water level in main tank and box become the same."

................................................................................

..................................

YAH..........got the idea if the outlet pipe is shut down the siphon will continue until it reaches a same height water level, it will stop siphonning...............

but the return pump is still bring back 2500l/h of water frm the sump mah............

if this were to happen the water will not over flow frm the box but frm the main tank...................

therefore in conclusion would measure the volume in the return compartment of the sump must not exceed the the wat ever volume left in the main tank...............

so even siphon stop pump will bring back the total amount of water left in its compartment but will not reach the top edge of the main tank...........

so at the most the pump run dry only rather than flood.................................

[weishun]

Erm... i let the experts do the talking.. i do the listening and studying. Hehe cos i not good in DIY. For the IBOX, i am slowly getting the picture of roughly how it works. Have been playing with the IBOX day by day and i am getting the understanding of how it works already and how to counter overflow problems....

[Navyblue]

In my previous post, there is something that is wrong hehe... I apologise (too late liao sleepy). So some point in this post will contradict from the previous post, so just ignore my previous nonsense hehe. It is actually not the U tube that on the external box that is lower.

In the external box, water flows over a "wall" from one "chamber" to the other. In order for the siphon to not break, this wall should be higer than the U tube inside the internal box, thus in all time the U tube is submerged under water and can not be exposed to air and thus siphon will not break.

All in all, the following requirement must be met in an overflow box to let the siphon not break. I read it from a site but I couldn't find it now.

A - The level of the U tube in internal box

B - The level of the U tube in external box

C - The level of the "wall" mentioned above

C must be higher than A and B. A can be higher, lower or equal to B. In this case i think your C is lower than A, thus when it drain too fast, A will be exposed to air and break the siphon.

Correct me if I am wrong.

[Domino]

Rule number one in Overflow boxes is that the siphon should never break. If the pump stops for waterver reason, the tank must not empty below th level of the overflow (this has more to do with the return pipe outlet as it will also act as a siphon when pump stops. when the pump runs again it should all pick up smoothly again.

when you operate the system, the tank level will rise a bit by a certain volume of water. That water volume must be provided by the sump fit in the sump without overflowing it.

FOR YOUR DESIGN TO WORK: the level of the divider in your ouside box should be a bit higher than the input level of your siphon tube (In the inside box). this will ensure that no matter what, the inlet and outlet of the siphon will never be exposed to air. Try it, you'll see...

[hermit]

you are right bro.........................

will do modification to the overflow box....................

hopefully can make the owner more satisfiying wif the products..............

thanks alot

[weishun]

Hahahah with Hermit's diy skills, i am more then satisfied. Hehe glad he will do the modifications for me. He a good friend...

[Navyblue]

Good luck

Nice acrylic work actually

I have a question for you Hermit.

How do you keep the internal box from floating up when it is empty? Or it is heavy enough to not to float up?

When I DIYed mine I can't think of a way to do it so I went with a U tube.

[FuEl]

A - The level of the U tube in internal box

B - The level of the U tube in external box

C - The level of the "wall" mentioned above

C must be higher than A and B. A can be higher, lower or equal to B. In this case i think your C is lower than A, thus when it drain too fast, A will be exposed to air and break the siphon.

Correct me if I am wrong.

A cannot be higher than B. If not your siphon will break. A cannot be lower than B... It would drain water from the compartment made by C in the external box back into the internal box. You'll have a broken siphon in this case too. Make A & B the same height and it will solve all your problems.

[hermit]

Hahahah with Hermit's diy skills, i am more then satisfied. Hehe glad he will do the modifications for me. He a good friend...

hey bro like tat say abt me......................

dam pai sei leh................................

my diy skills are VERY BAD leh.......................

not good handicraft skills btw......