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View Full Version : Connecting tanks with a syphon?


Bzar
05/13/2010, 11:30 AM
Just tossing an idea around in my head. I was planning on attaching another tank to my sump system. I was looking to drain my overflows into that tank, then through some bulkheads to another that hold the skimmer and return pump. But if I can make a syphon from the "overflow tank" to another using some upside down PVC U syphon channels then I wouldn't have to drill and bulkhead the tanks together. That also creates less chance of accidently cracking the glass by bumping the bulkhead connections. Anyone know if this syphon idea is a good option?

I was thinking of using 3 1" PVC upside down U channels for the syphon from one tank to the other. The tanks would be about the same height, and same level. Would that keep the water levels in each tank identical and provide a failsafe with say 1800 gph's through?

Thoughts?

USF Nealio
05/13/2010, 11:37 AM
I wouldn't do it. Can you position 1 tank 3 inches higher than the other? If so, drill 1 tank, and angle the pipe down into the lower tank.

Bzar
05/13/2010, 01:13 PM
hmm can't really do that it would defeat the purpose of the baffle system I have in the first tank. It's going to be acting as a detritus trap.

NoHooks
05/13/2010, 01:22 PM
If the syphon breaks, you'll overflow the first tank and burn your pump out when the second tank goes dry.

Bzar
05/13/2010, 01:38 PM
Ya that would be the primary concern with doing the syphons. Which is why I would do at least 3 syphon channels, maybe even 4 cause there is space for it. I was also just thinking of adding some airline tubing at the top of each channel connected to an aqualifter pump to keep a syphon in the channels. hmmm.

It seems like the same principle as using an over the top weir system that people use in their tanks for overflows.....what is the likelyhood that the syphon breaks in those systems? Perhaps I'll test it in a couple of buckets for a few days and see how it works since there's not much expereince with such a system it seems.

KANReefer
05/13/2010, 01:59 PM
Sounds like a risky idea

Bzar
05/13/2010, 02:33 PM
heh just found this interesting site...I'm thinking a concept like this.
http://www.aqua-bridge.com/

but between tanks in a sump

USF Nealio
05/13/2010, 02:41 PM
That's just a siphon. If air finds its way in there, it'll break that siphon, and you'll end up with a flooded floor.

TheH
05/13/2010, 03:00 PM
With the aqualifter pump I think it's doable. Many hob overflows work with this idea. One thing is I would put a strainer on both sides of the U-pipe.

Also, as to whether the water level will remain the same height in both tanks I think that will depend on how much water is being pushed and the volume of the pipes. It is possible that the water level in one tank might get an inch or two higher than the other.

Bzar
05/13/2010, 06:30 PM
any other thoughts on this?

Gin_Tseng
05/14/2010, 12:39 AM
Its would be risky....make sure to do a power failure test on your setup if you decide to do it.

coralnut99
05/14/2010, 06:28 AM
Years ago, I daisy-chained a bunch of smaller tanks in the fish room that way. It was really difficult to maintain water levels and yes, they can get clogged/obstructed. Unless the tank is very small and therefore the glass is thin, drilling and adding bulkheads is much safer. Whatever route you choose, you need to make sure you have enough overfloe capacity in the current sump in the event of a power failure, after adding the second tank.

TheFishMan65
05/14/2010, 06:49 AM
The problem is that the siphon relies in gravity so the water level in the drain tank must be higher than the second tank. I do not know your flow rate, but a sump us usually pretty high. I did something similar with 1 inch flex tube to get an extra 10 gallons of system water and to make water changes easier (drain the ten fill the ten). To handle a relatively slow rate (I am guessing < 300 gph) I had to have a difference of about 6 inches. Yes multiple paths would help some, but with out the water height difference it will never work.

Do you hae 2 spare tanks? Try it. Set them next to each other, fill them 3/4 full and add your siphon(s). Then pump from one (A) into the other (B). I expect you will have to raise B to get any decent flow.

This method also meant that I had to use a overflow type box (Capped PVC) in the upper tank so it would not drain too much.

Bzar
05/14/2010, 11:20 AM
yes good points all. Thanks for helping on the siphon topic. So lets look at the bulkhead method if we can :)

The path will be Display drains into Tank 1, then Tank 1 drains into Tank 2 through the bulkhead, then Tank 2 sends water back up to the display.

Question now is....should I put the bulkheads higher than the water level I want in Tank 2, or lower? Will it even matter? Will Tank 1 and Tank 2 equalize through the bulkheads if the channels are lower than the water line?

TheFishMan65
05/14/2010, 11:52 AM
If the bulkhead is large enough they will be equal. If it is too small you will have a backup in tank on that if you have a power failure will eventually make it to tank 2 and maybe the floor. I would use a large bulkhead place it at the height you want the level in tank 1 maybe a little lower (guess at the water height going through the bulkhead). The bulkhead sets the level in tank one. Total water in the system set the height in tank 1.

kcress
05/15/2010, 12:05 AM
Been running siphon jumps between three tanks for more than ten years. My tang would never let me stop using them. He'd cut my throat some night.

http://www.box.net/shared/static/vt29lxmj5e.jpg

TheH
05/15/2010, 10:22 AM
kcress, nice picture. So have you observed an uneven water level problem between the tanks?

stugray
05/15/2010, 11:43 AM
You dont need a "siphon", just use an overflow from the higher tank to the lower one.

I have a frag tank that sits above my sump.
One of my 125G megaflows dumps directly into it.
It has a PVC horizontal coast to coast overflow that then dumps into my sump.

http://i366.photobucket.com/albums/oo101/stuartjgray/Tank_details/my_new_frag_pendant_installed.jpg

http://i366.photobucket.com/albums/oo101/stuartjgray/Tank_details/slotted_frag_overflow.jpg

Stu

kcress
05/15/2010, 01:39 PM
kcress, nice picture. So have you observed an uneven water level problem between the tanks?


Never. The three tanks always maintain the same level until the flow starts to get up. As the flow increases the levels start to change. At 10gpm you will get about an inch difference in height.

TheFishMan65
05/15/2010, 06:58 PM
kcress,

How much area do you have in that siphon. That will make a big difference. As I said I was pretty small 3/4 inch vinyl. 3 1 inch would be much better than I had, but I am guess does not come close to what you have.

kcress
05/15/2010, 10:47 PM
Cross section is 6" x 2".

allset
05/15/2010, 11:09 PM
kcress,
Do you have a picture of all the tanks connected together?

kcress
05/16/2010, 12:46 AM
kcress,
Do you have a picture of all the tanks connected together?


Here's a link to the only readily available shot that shows both jumps.

It's a link because because it's long and needs to be large. (120k)

Both the center and right tanks have 1-1/2" pressure outlets in them. Because they both flow to the left tank the right jump is 4"x2" cross section and the left jump is a 6"x2" cross section as it has to support both flows.

This shot is during a wave cycle.

Note that the two right side tanks have six inch surrounds that the jump has to clear.


http://www.box.net/shared/static/pg4b4mnp4j.jpg

ChucksReefs
05/16/2010, 03:42 AM
I've been running a syphon for several years as the return between my refugium (vegetative filter) and my main tank. The biggest problem is that air does somehow collect in it and must be removed. I've added a small rigid tube to its apex and with a small pc of airline tubing and valve, air is quickly sucked out as needed.
Main tank > Overflow > Sump > pump > refugium > syphon > Main