pump, overflow, sump (need some help)

[psusocr1]

o.k got a question..
]my main pump is pumping about 600 gph +/- i want to add another 600 gallon pump, which id id..these pumps are minus all calculations with head, elbows, piping etc. anyway my overflow box is rater for 1400 gph
when i turn my new pump on it sucks the water right out of my sump, why will it not maintain a water level?? what do i have to do?? should i fill my sump all the way up then try it??
i dont get it??
any help would be AWESOME

 

[1911_guy]

Try adding a ball valve on the return line as far from the pump as you can. fill your sump and start closing the ball valve slowly until your overflow/return evens out.
Not an expert here but that's what I did and it works...if you have to close it more than halfway your pump may be too strong or you need more overflow.

 

[squidd]

So here's whats happening...
System is off...(as above) and levels all look good...When you start pump up, you need to "fill" the tank to the point the overflows can start working...That's where all the water goes..up in MT...once the MT is filled and flowing any "excess" water is returned to sump....
At this point sump level is dropping because you are sending an additional 4-5 gallons up to get MT "primed" and running....This is all good and to be expected...
So now, you'll need an additional say 4-5 gallons in sump to keep pump submerged and happy....so you may have to "add" that after it's running ...Still all good...
The danger is when you shut "off" the pump and all the "excess" water (4-5 gallon) drains back down..."backwash"...
You need to have enough "extra" room in your sump to be able to hold it ...or the sump will overflow....
The "excess" water going up (and coming back down) can be minimized to a point (there will always be "some" transfer) by adjusting overflows to siphon with minimal water height change and raising "anti-siphon on return to stop quickly in power out situation...
The rest of the "Backwash" room needs to be made up in the sump chambers...
Lowering skimmer chamber level (baffles) can help as well as return chamber level kept to minimum, but then you also need to deal with "evaporation" which will lower your return pump chamber level between top offs...
So...
When the sump, pump and overflows are working...you want the sump levels to be filled to blue and green levels...you may have to "add" water after fireing it up to get it there....
Then when tank/pump is "off"...excess water will drain back (backwash) and fill sump in the "red" zone....
This is all fine, normal and to be expected...
The danger lies in not haveing enough backwash area (red) to contain backwash in power out situation...

 

[1911_guy]

If you don't have a lot of room for backwash, try installing a check valve as a secondary safety device to keep the backwash to a minimum. Remember, the FIRST safety you should have is an anti-siphon hole drilled in your return line INSIDE the tank at top.
Check valves can fail and anti-siphon holes can get clogged, better to have 2 safeties. I've read some people drill 2 anti-siphon holes just in case one gets clogged.

 

[psusocr1]

well the problem of backwash i foudn out isnt a problem in a power outage because i drilled my syphon hole very close ot the top of my water so that it cuts the pump off immediatly...but i stillc ant get both pumps workign no mattewr how much wate ri put in my sump..i know there not too powerfull they are each only pulling about 600 gph if that!! and i know my overflow is rated for 1400 gph...what the heck am id oing wrong..i filled my sump up to the max, then turned both pumps on and it just sucks all the water out into the tan k and then stars suckin air until i shut thwm off??
and BTW thankx to both of you for helping!!

 

[1911_guy]

Originally Posted by psusocr1
but i stillc ant get both pumps workign no mattewr how much wate ri put in my sump..i know there not too powerfull they are each only pulling about 600 gph if that!! and i know my overflow is rated for 1400 gph...what the heck am id oing wrong..i filled my sump up to the max, then turned both pumps on and it just sucks all the water out into the tan k and then stars suckin air until i shut thwm off??
and BTW thankx to both of you for helping!!
did you try installing a ball valve? that's the only way to regulater the output of your pump. It will slow it down to where you need it. BTW, don't let your pump run dry.

 

[psusocr1]

no i never let the pump run dry...but it seems liek the flow when the new pump is on isnt reqally all thats much to begin with so if i restrict it anymore i dont think im going to get anything out of it??
you know what i eman?

 

[1911_guy]

No, I don't...I thought you were having problems with your pumps pumping TOO MUCH water back to your DT.
Help me out here. Is your overflow running dry or your sump? :notsure:

 

[robocop]

What is a anti-siphon?

 

[1911_guy]

Originally Posted by robocop
What is a anti-siphon?
A hole drilled into your return line just below the water level. If the pump goes out or electricty is lost you won't have pressure pushing the water up. The water in your return line will gravity fall creating a siphon, water will drain from your display tank into your sump through your return line flooding it. With an anti-siphon hole drilled once the water level reaches this hole it will put air into the lines breaking the siphon saving your sump from flooding. You can also install a check valve in your return line.
A check valve allows fluid to flow in only one direction. You install it so that it allows fluid to flow away from pump and into display tank, if pressure is lost the valve will close stopping a siphon from starting in the first place.

 

[psusocr1]

yes, i have a little giant and when its runnign it keeps a constant ater level in my sump, when i turn on my new pump it sucks the water right out of my sump like theres not enough water, although i added about 3 gallons of water!! basically it seems liek it is sucking wayy to much water out of my sump but on the other hand the flow out of the new pump is not really strong at all..im soo confused??

 

[1911_guy]

Don't worry about the flow, it's being slowed by head and bends...maybe even the size of your pipes. If the pump is pumping too many GPH then you may need to install a ball valve to control the output. Gotta go to work

 

[robocop]

Originally Posted by 1911_Guy
A hole drilled into your return line just below the water level. If the pump goes out or electricty is lost you won't have pressure pushing the water up. The water in your return line will gravity fall creating a siphon, water will drain from your display tank into your sump through your return line flooding it. With an anti-siphon hole drilled once the water level reaches this hole it will put air into the lines breaking the siphon saving your sump from flooding. You can also install a check valve in your return line.
A check valve allows fluid to flow in only one direction. You install it so that it allows fluid to flow away from pump and into display tank, if pressure is lost the valve will close stopping a siphon from starting in the first place.

That's confusing...if the siphon holes are below the water line in the sump and the pump goes off then the water would continue to rise not fall. The water draining back from the tank would cause the water level in the sump to riase.....how would the water level reach the holes if it's rising?

 

[rhomer]

Originally Posted by psusocr1
yes, i have a little giant and when its runnign it keeps a constant ater level in my sump, when i turn on my new pump it sucks the water right out of my sump like theres not enough water, although i added about 3 gallons of water!! basically it seems liek it is sucking wayy to much water out of my sump but on the other hand the flow out of the new pump is not really strong at all..im soo confused??

Perhaps it is sucking your sump dry to fill the pipe. If your using 1" pvc you might need 3 gallons of water in the plumbing alone.
Rob

 

[rhomer]

Originally Posted by robocop
That's confusing...if the siphon holes are below the water line in the sump and the pump goes off then the water would continue to rise not fall. The water draining back from the tank would cause the water level in the sump to riase.....how would the water level reach the holes if it's rising?
Siphon hole is drilled in the return line to the DT at the top inside the DT. Actuall mine isn't even below the water line. It just sprays a little stream out down into the overflow. The only water that returns to the sump is the water in the plumbing.
Rob

 

[fishntx]

also if you have any tipe of filter material in your overflow or wet dry the more the flow is restricted. it might read 1400gph but might only be allowing 1000gph. also the size of the drain pipe can restrict flow

 

[robocop]

Originally Posted by rhomer
Siphon hole is drilled in the return line to the DT at the top inside the DT. Actuall mine isn't even below the water line. It just sprays a little stream out down into the overflow. The only water that returns to the sump is the water in the plumbing.
Rob

What is DT? Does this apply to flexible return hoses? Would I drill the holes somewhere between the waterline and the top of the sump?

 

[rhomer]

DT = Display Tank
You should still attach a "flow tube" to your return line regardless of the tube type, and that should have a hole in it.
Rob

 

[robocop]

Originally Posted by rhomer
DT = Display Tank
You should still attach a "flow tube" to your return line regardless of the tube type, and that should have a hole in it.
Rob
When you say return line are you talking about the U shaped black think I have that connects to the flow tube then has a spout that sparys water into the DT? So I assume the hole would go at the top part inside of the tank?

 

[squidd]

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