Calfo Overflow Link

[ppurcell]

Hello, I'm using a gravity feed for my refugium and have worked out a way to avoid the drain lines sucking air along with the water which produces a lot of bubbles and salt spray in the display. But I cannot seem to get the water level to remain stabilized over long periods of time.

I have been hearing references to the Calfo Overflow, but cannot locate a link to a design page. Can anyone attach a link or pointer?

Here is a diagram of what I am using now and I'm looking for any suggestions on how to improve it.

 

[mr.wilson]

The "Calfo overflow" appears to be a venting system for a drilled tank with no overflow box (I'm going to have to start naming things after myself before all the good ideas are gone).The venting sound is dampened by a drilled end cap that regulates air intake. http://www.maast.org/modules/gallery/dow/aag

If you have slow flow (as you may have with your refugium) through any kind of siphon drain, it will tend to collect air bubbles. You may have to reduce it down to 1/2" plumbing to maintain suction and avoid draining quickly below the intake. raising the refugium will also help keep air out of the line. The Tom Aqualifter helps, but it needs a good platform to work from.

I would seriously consider drilling the tank. Siphon drains are dangerous in the best of cases. A good design should incorporate a overflow box within the refugium and a second box outside of the refugium. These boxes will assure siphon isn't lost and air bubbles are minimized.

 

[Randall_James]

Looking at your setup you are using a siphon? (aqualifter pump to keep running) and if the refugium is higher than the display, it is not needed.

Either allow the tank to only fill as high as the hole or only have the 1 elbow in the refuge with a stand pipe to adjust water level. no need at all for sipon as it will start and stop all by itself.

Just adjust the stand pipe to the correct length and allow gravity to do all the work for you

 

[jerryz]

Actually a calfo overflow is a toothless overflow. The laminar flow providing an increased skimming efficiency.

 

[ppurcell]

I had heard that a 'calfo overflow' (which is how it was described to me, anyway I was trying to research a solution to my bubble problem and thought it might help) was a means of setting up a gravity drain that would not introduce a lot of bubbles to the water as it passes into the display.

My refugium is drilled, but I guess that isn't clear in the drawing. There are two 3/4" bulkheads which are placed about 5" below the top edge of the tank.

Every configuration where I allowed water and air to enter the pipe has resulted in a lot of bubbles and salt spray from the bubbles popping on the surface of the display. A couple of hours of this and the salt spray completely covers the glass lens on my halides. The only semi-workable solution has been to use the siphon, with the problems I mentioned in my original post.

I don't think that if I invert the openings (with or without an overflow box) and add the vent, that would prevent the water from drawing a lot of air with it which in turn would result in bubbles and salt spray from the bubbles popping on the water surface.

 

[ppurcell]

I actually bought another brand new refugium tank that I could drill, add overflows to, or implement just about any other scheme to fix this problem. But I currently don't know what will work and I'd like to get it right this time, since the experimentation route is expensive, messy and time consuming...

 

[Randall_James]

The overflow you are talking about is a "horizontal overflow box"

In short is is an overflow box that runs along the top of the tank only.
http://forum.marinedepot.com/Topic26693-13-1.aspx

You need to build a bubble box on the display and ditch the sipon stuff on the refuge

 

[ppurcell]

So the right side option with a "bubble box" is what I should be looking to do?

Would the left option work any better? I have a spare hang on overflow box...

 

[Randall_James]

The issue you are having is at display with misting, the discharge from the refuge needs to go into a bubble box.

The unit you have on the right in the refuge is a horizontal overflow (only needed from the display to sump)

you need to baffle the refuge to display if I am reading your problem correctly.

A similar but inverted type box is used on the display. It can be filled with baffles, rock or even sponge to calm the flow and stop the spray.

You would use the same type of box you show on the right but it will have a cover (stops bubble spray) and have a few small holes to vent air. The other issue you may face is microbubbles in display, then you add rock or foam to the box to seperate out the bubbles further

 

[mr.wilson]

Sorry ppurcell, your post was perfectly clear; however, my brain obviously wasn't.

You need to first minimize the bubbles generated by the refugium drain, then discharge them at the surface of a return box in the display tank, as Randall_James has suggested.

This is one way of achieving both goals.

 

[ppurcell]

won't that create a detritus trap that has to be cleaned? Or possibly restrict the flow rate?

One thing that is nice about the siphon is that loose bits of chaeto flow through and down to the display for my tang to eat. With the bubble trap with rock and/or sponge in it that won't work any longer.

I guess I need to look around to find a design for a trap....

 

[Randall_James]

if designed correctly no detritus will build up due to the flow rate and turbulence. Same with the flow rate, it should not be restricted at all.

for now you could just cut a piece of glass or acrylic and cover the area of the tank where your return comes in. At least it will keep the spray off your lights

 

[ppurcell]

Is this sort of what you were describing?

 

[Randall_James]

wow nice graphics and yes something to that effect. You could still put a small splash hood over the top if there is any mist making it through.

I doubt you really need the box on the refuge to display pipe but if you have snails or other inverts in the refuge I suppose it could serve a purpose

 

[ppurcell]

Thanks, I wish I had the skill and patience to build what I can draw...

Do you know if anyone manufactures these things or are they more of a custom project?

 

[Randall_James]

Check http://melevsreef.com Mark is a competent craftsman for this kind of stuff for sure. Probably has something that will do you just fine

 

[ppurcell]

I was actually looking at Melev's site when your message came it. His site seems to be dedicated to DIY projects.

I don't see where it looks like he will do custom work for others.

 

[Randall_James]

Just shoot him an email... Melev is his RC name so you could PM him as well

 

[ppurcell]

Thanks for the pointer. I'll email him.