overflow

[vidul]

Hi all,

I need to know if the hang on type overflow boxes are reliable for getting water to flow into the sump...also how can a flooding into the main tank be avoided in case the flow into the sump breaks and the powerhead pushes all the water from the sump into the main tank.

Thanks in advance,

Vidul

[aftermath]

Hi vidul,

u shouldnt be afraid of the pump pushing water back from the sump. As the pump is always located at the last compartment of the sump, means only amount of water in the last compartment being sucks up. i believe u should hv reserved space enough for that.

u shld worried more abt main tank water siphon back to ur sump.

tats jus my 50c....

[vidul]

Righto !! Thanks for that ..so that means that the last compartment should not be large and just enough to have the powerhead submerged.

Also where can i find good overflow box design..can a simple pipe with gravity suction not work for getting water into the sump?

[colinsoon]

it can work, but

1. there is no surface skimming.

2. depending on how far you insert the pipe into the tank, the deeper the pipe the more water it draws out. this means if your sump is unable to hold the amount of water flowing into it, if the return pump stops, there will be a spillage.

3. a well designed overflow box, in any event the return pump stops, will syphon water out of the tank till the bottom of the overflow teeth. after which no more water will flow out. when power is restored, water will resume flowing out of the tank. dont have to worry bout starting it and stuff.

[rogersoh]

I found this overflow pipe design in this forum.

Attached is the image of the design. I had make the overflow pipe using 3/4 inch pvc pipe and its work perfectly.

[vidul]

Hi Rogersoh,

can you explaing the design.....is the red part the aquarium?

[Tigger]

Righto !! Thanks for that ..so that means that the last compartment should not be large and just enough to have the powerhead submerged.

Also where can i find good overflow box design..can a simple pipe with gravity suction not work for getting water into the sump?

Bro,

its not recommended with this kind of design. Reason being, if the last compartment is small, and u have a high flow rate pump, then the last compartment may be suck dry by the high flow rate pump. Also if u are not running chiller, the small last compartment, water level will drop very much and run the risk of pump run dry.

[aftermath]

hi,

to me i think just drill a hole and do a overflow partition in the main will solve all problems.

cheers.

[rogersoh]

Hi Rogersoh,

can you explaing the design.....is the red part the aquarium?

Yes the red colour is the aquarium.

I use this overflow pipe design because I got an existing glass tank without a hole i the tank to connect to the sump.

How it work:

During normal operation the overflow pipe ( this design is commonly known as Z pipe) is filled with water and the siphon break pipe is empty.

When there is a power failure or the sump return pump is switched off the water level in the tank partition (baffle is black colour piece in my diagram). The water level will drop until it is the same level as the "tee" joint between the suction break pipe and the discharge pipe to the sump.

The water level in the tank partition is above the opening of the intake of the overflow pipe. Thus the water will be trap in the overflow pipe shown as blue colour in the diagram.

When the power supply is back or the sump return pump is switched on the water level of the tank increase and so it the tank partion area. The water level raise above the "tee" joint the siphon effect kick in and the overflow pipe return to normal operating condition.

Initial starting of the overflow piping

This is the method I used

1. temporary seal the opening of the siphon break pipe.

2. suck the air out using a siphon pump at the discharge end of the overflow pipe.

3. once the water is flowing out, remove the temporary seal of the siphon break pipe.

My sump pump is Dolphin P2500 at 1300 litres per hour flowrate at 1.2 meter head, the 3/4" pipe is sufficient. REcommend to use bigger pipe if you want to have much higher flowrate. The flowrate depend on :

1. the height difference between the water level and the "tee" (bigger height difference higher flowrate)

2. the size of the pipe (bigger pipe more flow)

3. the friction loss from the piping and fitting.

hope this information help.

[Tanga]

Bro vidul do a search for diy overflow pipe there's alot of info in here. Below is 1 of the thread with good discussion.

http://www.sgreefclub.com/forum/index.php?...y+overflow+pipe

[vidul]

Great thread...thank you for that.

I need to know what capacity pump should i put for a 4 ft tank into the sump?

[dnutz]

Normal turn over rate for your tank you can use 3500 to 4000 l/hr if you want higher then can go for 6k or 6.5k. Do a search on turn over rate to find out more so you can decide which 1 you to go for.

[chrisyew]

Hi vidul,

u shouldnt be afraid of the pump pushing water back from the sump. As the pump is always located at the last compartment of the sump, means only amount of water in the last compartment being sucks up. i believe u should hv reserved space enough for that.

u shld worried more abt main tank water siphon back to ur sump.

tats jus my 50c....

Sorri can I ask if the siphon breaks, and the return pump such until the water almost dry in the last compartment of the sump; will the continuous running of the pump without water cause overheating and fire of pump??? Forgive me if it sounds silly.

[aftermath]

Sorri can I ask if the siphon breaks, and the return pump such until the water almost dry in the last compartment of the sump; will the continuous running of the pump without water cause overheating and fire of pump??? Forgive me if it sounds silly.

hi,

i mean that when u r not using an overflow box.

using a partition and a hole drilled in the main tank, dun even hv to worried abt overflow box siphon breaks or nt.

when the pump failed, u will only worried abt certain amt of water being auto siphon back to the sump.

see pic:

lets say when my pump fails....

water from the main will be siphon back to the sump till the YELLOW line as i had drill 2 holes on the outlet pipe to let air suction.

in sump,

GREEN line is the actual water level when the pump still works.

Water siphon from the main will stop at the RED line.

[chrisyew]

hi,

i mean that when u r not using an overflow box.

using a partition and a hole drilled in the main tank, dun even hv to worried abt overflow box siphon breaks or nt.

when the pump failed, u will only worried abt certain amt of water being auto siphon back to the sump.

see pic:

lets say when my pump fails....

water from the main will be siphon back to the sump till the YELLOW line as i had drill 2 holes on the outlet pipe to let air suction.

in sump,

GREEN line is the actual water level when the pump still works.

Water siphon from the main will stop at the RED line.

OK, this I understand with the hole drilled in the main tank.

My concern is actually the overflow pipe or the overflow box type.

[rogersoh]

OK, this I understand with the hole drilled in the main tank.

My concern is actually the overflow pipe or the overflow box type.

I understand your concern.

Refer to the overpiping diagarm in my previous mail.

When there is a power failure, the water level in the overflow partition will drop until it reaches the same level at the Tee joint. That is the level where the blue pipe meets the yellow pipe. At this instance the blue piping will still be filled with water. The siphon break only on the yellow pipe.

When the power return, the water level in the overflow partition will start to rise and as long as the water level in the overflow partition is above the level where the blue pipe and yellow pipe meets the water will start to flow thru the overflow piping.

So don't worry about the siphon break causing the overflow pipe to fail as this is unlike to happen. You can do an experiment by have the overflow pipe and switch off the return pump to check that it work.

[chrisyew]

I understand your concern.

Refer to the overpiping diagarm in my previous mail.

When there is a power failure, the water level in the overflow partition will drop until it reaches the same level at the Tee joint. That is the level where the blue pipe meets the yellow pipe. At this instance the blue piping will still be filled with water. The siphon break only on the yellow pipe.

When the power return, the water level in the overflow partition will start to rise and as long as the water level in the overflow partition is above the level where the blue pipe and yellow pipe meets the water will start to flow thru the overflow piping.

So don't worry about the siphon break causing the overflow pipe to fail as this is unlike to happen. You can do an experiment by have the overflow pipe and switch off the return pump to check that it work.

Thanks but think you misunderstood my meaning.

I'm not talking about the pump failure. In fact, I'm concern if the overflow pipe break siphons (maybe due to air bubble chock or some other reason), won't the return pump gets overheated once the last chamber run out of water? Is this why some need float switch to cut off the return pump if this occur?

[rogersoh]

Thanks but think you misunderstood my meaning.

I'm not talking about the pump failure. In fact, I'm concern if the overflow pipe break siphons (maybe due to air bubble chock or some other reason), won't the return pump gets overheated once the last chamber run out of water? Is this why some need float switch to cut off the return pump if this occur?

Sorry I misunderstood your meaning.

Yes I agree that a float switch will prevent the pump from running dry.

[chrisyew]

Sorry I misunderstood your meaning.

Yes I agree that a float switch will prevent the pump from running dry.

Oh that means a float switch is mandatory if such a overflow pipe is used.

[Tanga]

Oh that means a float switch is mandatory if such a overflow pipe is used.

Bro if your sump last compartment is small it will cause the return pump to run dry that if the overflow break siphon. If it's too big it will flood your main tank and run dry your return. So getting a float switch is like a back up plan.

Anyway any overflow that you using will have some percentage to break siphon due to so many reason.

[chrisyew]

Bro if your sump last compartment is small it will cause the return pump to run dry that if the overflow break siphon. If it's too big it will flood your main tank and run dry your return. So getting a float switch is like a back up plan.

Anyway any overflow that you using will have some percentage to break siphon due to so many reason.

Thanks Tanga.

So the best bet is still to have a hole drilled into the tank for IOS? For IOS, is it no more need to have a float switch to cut off the return pump as it sure won't break siphon?

Thanks once again.

[Tanga]

Bro I'm using IOS tank but still have some worries of the return pump running dry. Saw a diy float switch set at Sim Lim Tower for $60 maybe planning to buy just to play safe.

[chrisyew]

Bro I'm using IOS tank but still have some worries of the return pump running dry. Saw a diy float switch set at Sim Lim Tower for $60 maybe planning to buy just to play safe.

That's what worrying me too hehe.

But besides buying a float switch, still have to buy a relay or a controller - then the amount of $ may not be juz $60 right? Anyone knows what relay to buy to cut off the pump and how much will it cost?

Thanks.

[Tanga]

Bro its a set so should have everything anyway will be going down to SLT this weekend to ask the pricing and find out whether its really what I think it is.

[chrisyew]

Bro its a set so should have everything anyway will be going down to SLT this weekend to ask the pricing and find out whether its really what I think it is.

Thanks Tanga. If it's $60 including the relay to cut off the pump, then it's really worth getting one.

Pls keep me posted here. Thanks once again.