PVC Overflow Plans???

[redhat]

Does anyone have plans or pictures of PVC overflows. I can't seem to find much about them anywhere. I'd really like to try building one instead of having to drilli tanks.
Thanks
in advance.

[gary1218]

Is this what you are looking for. I make these.

http://forum.simplydiscus.com//index.php?board=13;action=display;threadid=5418

GARY

[wall_o_fish]

This guy came up with a pretty cool PVC overflow design (plus some serious graphics skills!).

http://www.nd.edu/~lego/grp2/www/reef_diy.htm

scott

[limige]

in my post on wet/dry's on the second page i have some pics of a 3" pvc tube used as part of a overflow.

http://forum.simplydiscus.com//attachments/overflowdone.JPG

i siliconed a peice of glass to the bottom of the pvc to hold it steady and stop the water from draining. you could also replace the j pipe with pvc.

i recently emptied the tank and siliconed two peices of glass into the corner instead and used the same overflow box on the rear.

[dred]

Redhat,

I don't have plans, but I can explain how they work. You shouldn't have a problem designing one to meet your needs.

Essentially, and overflow box is just a siphon into a secondary water container. The siphon will naturally maintain the same water level in the two containers it connects.

Now, since you want to drain from the overflow box, it is just important to make sure you don't disrupt the siphon when pulling water from the overflow tank. This is easily accomplished by making sure the tap or drain in the overflow container is more shallow than the actual siphon that feeds it. This way, you protect the integrity of your siphon.

So, create a siphon and a secondary water container. Then tap the secondary water container at the level you wish to maintain in the actual tank, while making sure that the siphon outlet is deeper than overflow tap.

The fancy engineering options in this setup relate the speed at which the siphon can evacuate the overflow (more siphon tubes or larger diameter tubes increase flow), and the elegance by which the siphon is created.

hth, milton

[trucdan]

limige,
Could you tell me how to bend the U shape siphone tube? I can't find it at the LFS. Try to bend it with a heat gun and a propane torch but it doesn't work. Thanks.

td

[Jason]

I've never bent pvc tubing, but the clear acrylic type used in undergravel uplifts, and hydro's etc is real easy to bend.


go to the lfs and buy a piece that's longer than you need, with a heat gun soften up one end and crimp it shut.

now fill the tube with sand or someting that doesn't melt and crimp the other end shut.

next, hold the piece over a heat gun or stove element, slowly soften up the plastic and bend it in little increments, until you have the shape you want.

now drop it into an ice and water bath to set the bend, saw off the crimped ends, dump the sand out, and you're all good.

dont use a flame it will scortch and discolour the plastic.

I imagine instead of sand you could use those springy lookin things plumbers use to bend copper pipe without crimping it, but havent tried it.

give it a try! even if you mess a couple up, the stuff is cheap.

[trucdan]

Jason,
Thanks for the great tip. I bought a 8 feet long acrylic tube and almost broke them all until I got your tip. I made one this morning :D. However, I can't make it perfectly round. At the curve portion, the tube is not really round. How do you make a "perfectly Round" tube?

Any way, thanks for the tip.

td

[Jason]

too get it perfectly round, you really have to pack the sand in tight.

hold it over a stove element and bend it slowly, if it starts to kink on you stop, and heat it up a little more then form it with your fingers, dont burn yourself, use gloves if you have too- I've got no feeling left in my fingertips so the hot plastic doesn't bother me.

HTH!

[tomanystraydogs]

I am new to this so please excuse my ignorance.

I understand how a siphon can draw the water from one tank and put into a sump.

But how do you get it from the sump back to the tank? If you use a pump don't you have to some how match the flow of the siphon?

If the pump does not fill the tank quickly enough, the siphon will break and/or the sump over flows.

If it fills it to quickly, the sump could run dry and/or the tank would fill faster than what the siphon could handle and the tank would over flow.

Just trying to work this out in my head, I have no real experience at it.

tia

[tomanystraydogs]

Wait, I think I got it.

Instead of having a sump that is much lower than the tank, this setup is another tank at roughly the same height as the main tank.

That is how you are able to get the water back into the main tank without a pump, correct?

[Jason]

incase of pump failure, you have to make sure the sump can hold the amount of tank water it takes leaving the main tank to the level where the siphon will break.

you try to match up your siphon's flow-rating with the pump you choose, head pumping height is important too.

you can then fine-tune the set-up by either installing a valve between the overflow and sump, or you can put one on the line return from the pump to the tank,

there's other ways too but these are the most conventional, have a look at some manufactured set-ups and check-out how the work.

hth

[tomanystraydogs]

Thanks, guess I was closer to being right the first time :)

Let me ask you this.

Assuming you have 2 tanks side by side, couldn't you siphon from tank 1 to tank 2, then also siphon right back from tank 2 to tank1?

[Smokey]

Water will level out at the same level.

Between two containers - water will flow from one container to another untill there is a balance of surface pressure. Then the flow will stop. The syphon will still be ''LIVE'' ; however - it will be in equaliberium.

One suggestion - place an airstone in one of the connectiing tubes ... and adjust the air flow so water will be air-lifted from one unit into the other.
This will maintane a ''FLOWING STREAM'' between the two tanks.

Smokey