Calfo Style Overflow boxes

I just used the calculator on the home page, and it looks like I can get 400gph out of a single 1" bulkhead... I think that one of these plumbed to the sump, and 1 extra for emergency would be a good idea... I could just put an elbow on the extra one, and turn it up then when/if I ever need it, all I have to do is turn the 90 down... I would of course have to make both of them run together to do this, but that is not a problem

Thanks,
 
One more question... When that calculator says that you should have .86" min diameter drain pipe... that means 1" pipe right?

also, when it says that you need 6" min. linear overflow size... what does this mean (linear)?
 
<a href=showthread.php?s=&postid=10225427#post10225427 target=_blank>Originally posted</a> by lukinrats
I like the route that GuySmilie took, and am wondering if you can cut that slot out w/ dremel on a glass tank, or if you have to have an acrylic tank... Also how hard is it to do this on glass?
Click to expand...

Mine is cut in a glass tank, but it could be done on an acrylic tank as well, provided you didn't diminish the integrity of any support or bracing pieces of the tank.

Mine was done with a router rigged with a glass cutting bit. My local glass shop has the right stuff to do it so it was cheaper for me to let them have at it. I suppose it could be done with a Dremel, but you'd better have a steady hand! And some sort of a tool guide would definitely help keep the cut straight. Just keep in mind that any accidental 'slips' or 'dips' or 'deviations from absolute parallel' will affect how smoothly the water will flow over the edge of the cut.

I plan on running about 400 gph through the sump, so I thought that if I did my overflow that way... I can run 1 to 2 bulkheads directly to the sump... 1 to the skimmer... 1 to the Fuge... Does this sound acceptable, and what size bulkheads do I need to get 400 gph running through 2 of them, or just 1 if it will do it
Thanks,
Click to expand...
You can never have enough drains. As long as you've got the room for them why not add a couple more than you think you will need? You can plug any extras shut for now. Because once you get it filled with water its a real pain in the rear to add additional drains then. I already wish I would have added a 4th one to mine. :(
 
I wanted as much volume back there as possible. As this adds to the total mass of water in my system (a good thing). But since my usable space for an in-cabinet sump was rather cramped, I was limited to using a 20g long for a sump. As you know, a 20L is not a very deep tank. And to compound the problem, I am using a pretty hefty internal return pump (OR3500) that needs a fair amount of depth of water just to keep it primed. No room to mount it externally.

All that, and the fact that you must have enough empty space in your sump to hold everything in the event that something on the topside fails, breaks, or leaks.

So with all that said, I limited my overflow chamber to a volume of about 3 gallons - due to my smallish sump.
 
My sump should hold around 20 gallons for operating volume, and be about 30 something total volume... What I was looking @ is the calculator on the home page says you need 6" of minimum linear overflow size to accomodate 400gph thru a 1" drain... So, my question would be, what does linear size mean... Is that 6" cubic, or 6" long x 6" deep x 6" tall? I dont know
 
6" linear means 6" long. It could be 2" x 2" x 2" if you wanted. You can't go wrong with making it longer, though.
 
It's 6 inches wide.
The horizontal space between these two vertical bars is the lineal area:

|_________________|
 
If this is OT...sorry.......


Im sure this has been done before......but here is my ghettofied version of a near coast to coast overflow "box" using nithing but 2 bulkheads and some PVC pipe. I set up a 46 gallon tank for a friend and came up with this. I use external coast to coast overflows on my tanks, but this was a super simple way to achieve near coast to coast surface skimming, it took less than a 1/2 hour to make and install and you cant even see it in the tank.

simply put.....2 bulkheads, 4 street elbows inside the tank and a piece of pipe with a groove cut out on the table saw 3 notches wide. The overflow is removable by simply lifting it out. The street L's are water tight this way. that part kind of surprised me as i figured over the course of a night it would drain down to the bulkheads...but they didnt.

pics...this of course doesnt go the entire length of the tank, more like 2/3...but it just as easily could have, and it skims the surface great. Its also no louder than the Snapper used to power the CLS.



overflow1.jpg


overflow46plumbing.jpg


overflow2.jpg
 
Flyyyguy - I really like that idea for an overflow. It seems like you would be able to regulate the water height by just rotating the slot in the PVC higher or lower. Does that make sense? You said the slot was 3 notches wide. About what does that measure?
 
Im not sure how much that measures to be honest. I ran it through my 10" table saw 3 times with just a standard blade. The tank isnt here or I would measure it. I would guess 3/16"....


Actually, I DO have the slotted pipe glued into two of the street 90's., so it coouldnt be twisted. The height can be changed by lifting or lowering that entire pipe and the 2 street elbows. That assembly is not glued into the street elbows hooked into the bulkheads.

I think if you twisted it it would actuall take away some of the surface skimming action vs the slot being dead centered on top

I got lucky as far as my slotted pipe assembly being water tight into the bulkhead and 90's. But even if it wasnt, a touch of silicone grease could fix that. Thats what I planned on using to seal it and still make it easily adjustable/removable for cleaning, but just didnt need to.
 
Flyyyguy: How's your flow?

On most of the Calfo overflows I've seen the top is wide open. More water is processed through your overflows. I'd imagine the slot would be cause a restriction that might slow down flow to your sump. Does this sound right????

BTW: What a great idea! If no one has any thoughts on restricting the flow I may give that a shot. Thanks.

Ordy
 
One more thought: I spaced my two overflows about 6 inches apart. If I wanted to go coast to coast could I use a 1" tee instead of a street elbow and extend it to the other end of the tank? I'm really liking this idea!

Ordy
 
<a href=showthread.php?s=&postid=10231242#post10231242 target=_blank>Originally posted</a> by ordy1
Flyyyguy: How's your flow?

On most of the Calfo overflows I've seen the top is wide open. More water is processed through your overflows. I'd imagine the slot would be cause a restriction that might slow down flow to your sump. Does this sound right????

BTW: What a great idea! If no one has any thoughts on restricting the flow I may give that a shot. Thanks.

Ordy
Click to expand...

I doubt it restricts flow. The water going over my Calfo overflow is only about 1/8" high and deep. I would imagine that the pipe concept would not restrict flow in any way.
 
i would think as long as your slot in the top square inchs is equil or greater than your bulkheads you will have no problems and take a thin skim off the top. i only see one drawback to this, and only one. i think it would be alot harder to get paralel with the top of the tank so u can get all the benys of calflo.
 
<a href=showthread.php?s=&postid=10235615#post10235615 target=_blank>Originally posted</a> by customcolor
i would think as long as your slot in the top square inchs is equil or greater than your bulkheads you will have no problems and take a thin skim off the top. i only see one drawback to this, and only one. i think it would be alot harder to get paralel with the top of the tank so u can get all the benys of calflo.
Click to expand...

that's a good point. i didn't think of that. you're right.
 
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