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BROKER

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Works great but is throughing alot of bubbles. It is hooked up to a Mag7 on my fifty at hour feet (460gal/hr). Any ideas on how to get rid of the bubbles?
 

SPC

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Broker, first of all why do you have 4' of head, is the pump on the floor?
Second, how far away is the intake from the output?
Steve
 

BROKER

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Yeah, it is on the floor. I figured if I mounted it higher I would have to much flow. The intake and the output are about 6" apart. Should they be further apart?
 

2poor2reef

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Broker, on a closed loop with both input and output under water you shouldn't be getting any bubbles. I have a Sen 700 driving two 1/2 inch stubby sea swirls and I occasionally get a vortex from the surface that will throw a few large bubbles around the tank for a few seconds but that's it. My nearest output is about 18" from the input strainer. If the input is fairly low in the tank that helps as bubbles tend to rise. Also, IMO it is better to run minimal head in a closed loop and use a gate valve to reduce flow if necessary. Leaves you more options.
 

BROKER

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My input is only about 2" in the water, so I will make it longer. 2poor2reef, how far is your input in the water? I will also seperate the input and output futher. I agree on the minimal head and the options now that I see the swirl in action. As soon as I get the Y fitting on it I am going to move the swirl to the back of the tank. I will go to home depot (24hrs
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)and get the gate valve. Any other ideas on what might be causing the bubbles? Thanks for the replies.
 

esmithiii

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Remember that for a closed loop system, the only thing that contributes to head pressure is the length and diameter of the tubing and the number of bends. Height of tank does not contribute to head loss as it does when you are pumping from a sump.

E
 

SPC

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Ernie, your going to have to explain that one. How does head preasure change just because its on a closed loop?
Steve
 

2poor2reef

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My input to the closed look is about 12" below the water line. If you can move yours then I assume your input is not via a drilled bulkhead in the side of the tank. I've used the y fitting on mine also and also the flared fitting works well too. Good luck.
 

esmithiii

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Not true. Why does a siphon work? The weight of the water going down to the pump is equvalent to the the weight of the water going out of the pump! This cancels out the "Head Loss" and the only head loss in a closed loop system is due to the friction of the water going through the pipes, which is proportional to the distance of the pipes and inversely proportional to the square of the diameter of the pipe, roughly. Bends complicate things a bit.

Think of it this way: The potential energy of the water is not changed, only the kinetic energy.

In a sump system, the water flowing into the sump looses potential energy (turned into kinetic as it accelerates into the sump) which is lost by the time the water is sucked into the return pump.

Its like a car (engine off) at the top of a hill. When it goes down a hill, it gathers speed (accelerates) and if there is a second, equally high hill, it will go up the hill (almost, due to energy lost to friction). If you want to go all the way up the hill, you need a motor (like the pump in a closed loop) to overcome the friction. The energy used to overcome friction is the same energy used to propell the car and equivalent distance on a flat surface!

This is physics 101 stuff here.

Interestingly enough the position of the intake and exhaust in a closed loop system makes no difference to the head pressure issue as long as both are under the surface of the water.

I know that it sounds a bit counter-intuitive, but it is fact.
 

2poor2reef

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That's interesting. I should have taken phsyics 101. However, use of a gate valve on the loop would still allow you dial in the desired flow would it not?
 

esmithiii

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Yes. A gate vave would be ideal if your pump is rated for backpressure. Some are not.

The Physics 101 comment was probably a bit much, eh? Sorry; didn't mean to offend.

Ernie
 

SPC

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Thanks for the reply Ernie, makes sense now, and I did take Physics 101 about 32 years ago so please forgive me for being a bit rusty.
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Steve
 

esmithiii

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Steve,

I wasn't alive (by pro-choice definition) 32 years ago! Careful, you will reveal your age.

Broker:

Would love to see pictures of your closed loop as I may do one myself.

Ernie
 

BROKER

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Reefland,

What did you use as the screen? That is a great idea. By the way my closed loop is very similar to yours except I only have one gate valve. Any reason for the two?

Hopefully my other Christmas wish will come true. Smile fishy your on reefs.org
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BROKER

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Just an update. First I would like to thank 2poor2reef in helping me get rid of the bubbles. Also like to thank esmithiii for the lesson in physics(no I am not being sarcastic). Just to add some info the cls needs a few days to break in. Kind of like a skimmer. With the combination of the swirl and refugium any traces of algae have disappeared. My calupera and halemida algae are growing well. All water parameters are stable and corralline algae is growing extremely better with diameters of approx 2inch (pain the a** to scrape off). I set up the cloosed loop and the refugium to reduce the amount of water changes to once a month. It has been three weeks since my last water change and everything is fine. If anyone needs or wants more info let me know. I am amazed how well things have turned with the addition of this equipment! Wish I had a camera.

I would also like to add that thanks to the members of this board and the information I have used to set up my tank I know feel much more confident I can maintain a reef and I am ready for my first Dr.Mac coral (hopefully for Christmas
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).

Now I just need to work on my spelling.
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[ December 10, 2001: Message edited by: BROKER ]

[ December 10, 2001: Message edited by: BROKER ]</p>
 

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