Overflow Idea.. pls check it out.
- Thread starter Ansphire
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twok2lcdcnc
Member
Let's take a second and review "basic physics".
let's say you have a 125g tank. The "blueprint" you went out of your way to design shows the inlet of your overflow at a little lower than halfway down the tank, but I'll give you the benefit here and say it's only half way.
The power goes out.
Your return pump stops pumping.
60+ gallons (about 500 pounds of water, optimistaclly) is ABOVE the inlet for your overflow.
the water pressure alone will empty MOST of that water into (and out the top of) your sump.
But not all of it, because when it gets near the end, it'll break siphon.
twok2lcdcnc
Member
MeuserReef
Welcome to the next level
<a href=showthread.php?s=&postid=12140452#post12140452 target=_blank>Originally posted</a> by twok2lcdcnc
Let's take a second and review "basic physics".
let's say you have a 125g tank. The "blueprint" you went out of your way to design shows the inlet of your overflow at a little lower than halfway down the tank, but I'll give you the benefit here and say it's only half way.
The power goes out.
Your return pump stops pumping.
60+ gallons (about 500 pounds of water, optimistaclly) is ABOVE the inlet for your overflow.
the water pressure alone will empty MOST of that water into (and out the top of) your sump.
But not all of it, because when it gets near the end, it'll break siphon.
Incorrect my good man! Water has whats called "gravitational potential energy" as it sits in the tank. Because the outside pipe RISES above the static level of the water in the tank, and because the tube is open to air (indicated by a half-full "T" at the top of the riser tube), there is no suction created (siphon) nor is the water able to resist gravity and go upward (gaining gravitational potential energy without the aide of a pump (or some other outside force doing "work" to make it rise) violates the Law of Conservation of Energy)
Basic Physics
twok2lcdcnc
Member
okay, if so, then how does this design work at all? And what are the benefits of doing one like that? Am I missing something here?
MeuserReef
Welcome to the next level
No offense to the OP, but I dont think this design WILL work well. The only benefit, was so that he would not have "clutter" in the tank.
I would opt for an external overflow box that would then have a standard Durso overflow tube.
BTW... If the standpipe was NOT open to the outside air, then, as you stated, the tank WOULD drain to the level of the bulkhead if the power went out.
Cheers!
stugray
Premium Member
As the pic in the OP shows, the level in the tank must be above the "Tee" in the outside portion of the pipe for any water to flow down the "outflow" pipe.
If you lower the water level in the pic just a few percent, the level in the outside portion of the pipe will be low enough that water will no longer be able to make it out of the "outflow" pipe, and the draining will stop.
Stu
If you lower the water level in the pic just a few percent, the level in the outside portion of the pipe will be low enough that water will no longer be able to make it out of the "outflow" pipe, and the draining will stop.
Stu
BeanAnimal
Premium Member
The design works because water seeks its own level. Basic physics
There are no real benefits for a fish tank that needs surface skimming. On the otherhand if we were trying to draw drinking water from below the surface of a scum covered pond, it would be perfect.
Fishbulb2
New member
<a href=showthread.php?s=&postid=12141814#post12141814 target=_blank>Originally posted</a> by eznet2u
Maybe this will explain things a little better...
That is exactly what was missing. The original posts didn't make the bulk head obvious. It just looked like it was going up and over the tank frame. This clears it up for everyone. Still, I don't like the idea of not surface skimming. That would be a deal breaker for me.
edit, sorry it was colotl's post that confused me. The original post actually show a very similar figure.
Aqua Keepers
New member
Do you guys have more info on the PVC overflow for nondrilled tanks? I assume there's not much surface skimming going on in this type of set up.
BeanAnimal
Premium Member
That will not do nearly enough surface skimming to be effective... Also, I think you will find that the setup will be rather noisy, depending on the flow rate and pipe size.
MeuserReef
Welcome to the next level
Bean... your PM box is full
Aqua Keepers
New member
That's what I figured. Bean (or anyone else), do you have any links on how to build an overflow for a non drillable tank? I have melve's link but his requires a router and bending of acrylic. I'm looking for a simple cut and glue build. Sorry, if I'm stealing the thread.
BeanAnimal
Premium Member
<a href=showthread.php?s=&postid=12149618#post12149618 target=_blank>Originally posted</a> by MeuserReef
Bean... your PM box is full
Fixed
