Calfo overflow?

[lmn420]

I am considering doing something similar to what I have seen called a calfo overflow and was wondering if anybody had any good/bad experience with a calfo overflow?
I know this isn't a coral question but I noticed a similarity between Anthony Calfo's name and the overflow. Thanks
Lindsay

 

[kgross]

You are correct in that Anthony was the one that suggested this to most people.

I love a long overflow. It does not need to be full length most of the time, but the longer it is the better surface skimming you get.

Kim

 

[Bainic]

I looked it up and was intrigued by the concept. But a couple things posed concern to me. For me, it would have to go coast to coast (all the way across the back), because if it only went for a portion of the back of your tank, there would be dead spots on each side where there was little to no flow. The same goes for the underside of the overflow, you would be creating a right inside angle where there would be little flow, and stagnating, oxygen deprived water. On the plus side I really like the idea of having so much surface skimming to eliminate alot of waste and nitrates from the water.

 

[kgross]

Not going all the way to the end does not create a dead spot, the water can come over the ends of the overflow, so it acts just like a normal reef ready tank.

On under the overflow, you are correct, but I have not found it to be an issue. You can make the bottom of the box angled though so it is not a right angle, you could make it around a 60 degree angle which would help, you would just have to cut the sides to match.

Kim

 

[lmn420]

I have gone as far as creating the box to place around the bulkheads, but I am not sure I am going to use it since it seems to take up a lot of space. Besides increasing the area of surface skimming are there any other benefits? Thanks,
Lindsay

 

[kgross]

To me the biggest benifets are the increase surface skimming, and to me it takes up less space in the tank, since you can make it really small just long, it does not take up any room for rock or corals, unless you have a thin tank and do the wall of rock...

Kim

 

[lmn420]

well my problem is the bulkheads I am covering are 1.5" so to fit an elbow in the overflow box I had to make it stick out 5" so while it doesn't take up any space at the bottom of the tank it does take up significant space at the top (30x5 to be exact). Do you know of a way I can make it thinner? Can I get away with not using the elbows?
Lindsay

Edit: If I don't use the overflow box I was planning on just putting some strainers into the bulkheads and calling it good. Is that a bad idea? Thanks for answering these stupid questions kim.

 

[kgross]

One thing you can do is cut the elbows down. I cut the end off of them to make them as short as possible. What I normally do is use 1 inch fittings, and I can make the box 2 inches front to back by 3 inches tall...

The strainers will work, but you will not get much surface skimming and it might be pretty noisy to be honest.

Kim

 

[lmn420]

well I was just thinking about how all my problems come from the fact I am trying to fit elbows in the box. So what if I just don't use elbows and leave it as it is? As I type this I realize that the elbows redirect how the water enters the overflow, but what does that do? Make it quieter? I don't want to restrict the flow on the overflows by using the 1" elbows so I think I might be stuck with the big box or no box. Dang.

 

[kgross]

The elbows keep them quite, by not allowing a swirl to start. But you can go with out them, if you put a shield over the top of the bulkheads to keep it from swirling. Then you can make the box only an inch or so front to back. Just inside the box above the bulkheads, put 1/2 of a piece of 3 inch pipe so that the water has to come from closer to the bottom of the box rather than the top. This is what glass-holes does inside of there boxes to keep them from being so large.


Kim

 

[lmn420]

simple and effective that sounds like a good solution, but what would you do if you ever needed to remove the bulkhead? There wouldn't be enough room to pull it out. hmmm might have to just make sure the bulkheads will never leak and hope for the best. Thanks so much for your help Kim, obviously I have nowhere near the experience and knowledge you do and appreciate the fact that you are willing to answer these newbie questions. I will have to post pictures after I get everything situated.
Lindsay

 

[kgross]

You are very welcome my dear.

What you can do to make sure you can get the bulkheads out, would be to silicone the cover in place rather than glue it to the acrylic box. Then you could remove it if needed and just silicone it back into place..... or even use some weather striping to hold them in place.... just brainstorming a couple of ideas for you.

Kim

 

[lmn420]

So I went to home depot and found some 1.5" elbows that are male threaded on one end and like you suggested I cut the other end off it so it takes up much less room than a full elbow allowing the overflow box itself to be much smaller. Now I just need to trim down the box I have and cut tons of slots in it (time to bug my friend with the rotozip).
Lindsay

 

[kgross]

I would not worry about the slots to be honest. You will get better surface skimming without the slots and less algea growing on it. For a cover just put a piece of egg crate over the top of the overflow, works very well.

Kim

 

[lmn420]

I am glad you are here to point out the obvious. That will make it so much easier and as you say it will work that much better. Thanks again!
Lindsay

 

[lmn420]

well I finally got around to installing the overflow box and low and behold I made the classic bonehead mistake of making the box too short to cover the drain holes (doesn't make for effective surface skimming). I added another inch to cover the drain holes and now it is an inch higher than the corner overflow so do I need to raise the corner overflow or can I get away with the differing overflow heights? It won't exactly be easy to raise the corner overflow since it already has grating installed that would have to be removed or worked around. I will water test it this evening and see how it works currently and maybe try to raise the corner overflow without removing the grating (any ideas on how to do that would be appreciated). Thanks,
Lindsay

 

[kgross]

I have no good ideas on raising the corner overflow to match the new one. But what would happen if you just stopped using the corner overflow (valved it closed), and let the new overflow handle all the water?

Kim

 

[lmn420]

Yeah I could do that. It just seems like such a waste of space. I will see how it goes tonight and then decide what to do with that corner overflow.

 

[kgross]

I would agree with the wasted space. I just don't have any good ideas on how to even out the 2 different overflow boxes.

Kim

 

[lmn420]

I think I might just glue some thin acrylic I have on the front of the grating to raise it up to match the other overflow. It shouldn't need to be very strong since it is at the surface and all. If that doesn't work I might just completely rip out that overflow, I just don't want to have to reroute the return line and close that drain.