Originally posted by grovey
okay i'm reading this it's 6 am and smoke is rolling out of my ears
question mr. squid
Do you need a pump to bring water to the sump or can you just let gravity do it's thing
or do you need to speed up the water flow for flow thru out the rest of the cycle
No need to pump water "to" the sump (as long as it's below the Main tank) Gravity will bring the water down as fast as it "becomes available" (as long as overflow can handle flow rate)...
Here's a "Visual Aid"...You can do this in your head (clear the smoke ), Draw it on Paper , or Go Out and actually "build this".....
Take a 5 gallon bucket...Drill a 3/4" hole in the side...
(that should do 300gph) Represents "overflow" ....
Take a 1 gallon bucket and start filling the 5 gallon bucket at a rate of 1 gallon every 15 seconds...(4 gallons /minute or 240 GPH) ...(represents "pump)
How "Full" will the bucket get...??? Only up to the level of the hole...and then Gravity "drains" it out...No need to "pump" it out...
The pump (you) is "sized" less than overflow capacity (3/4" hole) and tank level remains steady...
Now take the 1 gallon bucket and start filling the 5 gallon bucket at a rate of 1 gallon every 10 seconds...(6 gpm or 360 gph)...
How full will the bucket get...??
First it will fill to the level of the overflow and "MOST" of the water will "drain" out...(300gph) but as long as your putting more water "in" (360 gph vs. 300gph) the water will continue to rise and eventually overflow the bucket (your tank) because...
The pump (you - 360 gph) is "sized" greater than the overflow capacity (300gph) and the tank will continue to rise and flooding wil result
Gravity can not keep up...but we don't want to deal with "pumping out" of the tank..So It's important to Size the pump to fill the tank at a rate Less Than the overflow can take out (drain)...
The "second" part of your question is a different aspect ...
the only reason i ask this is if you go with a syphon effect it wouldn't make sense to use the syphon why not just put the pump taking the water out of the tank and work it so you have the same flow return? [/B]
A "siphon" is different than a "drain" in that...A drain will start and stop when the water reaches it's level ..the "level" is set "mechanicaly" by the height of the standpipe or the "placement" of the hole...
A "Siphon" is dependant on two water levels and is always trying to "equalize" them as long as the siphon is "functional" (there is water in the tube) ...
The "ends" of the tube can be at "any" depth or level (as long as they're submerged) and the water will always flow from high to low...
So at "this point" a siphon will bring water from upper tank to lower sump...(functioning)
But what sets the "depth" or level in the tank...??
The water will continue to flow from higher to lower level until the siphon tube "sucks air" and the siphon is broken...and once "broken" cannot "restart" itself...
So what happens when the power goes out...?
The siphon wil continue to drain the upper tank (till it "sucks air and stops) and if the end is too low will... A. Drain your tank..B. Flood your sump...
And what happens when the power goes back on...??
The tank will fill, the siphon can not "restart" itself if it has air in it, the tank will overflow and flood the room...
So...a "siphon" is a "functioning PART" of an overflow, but cannot be used on it's own...
Visual discription of "siphon" and "drain"....