Retrofitting a horizontal overflow to existing vertical overflow

RobertK

Premium Member
Hi there,
Has anyone installed an internal horizontal overflow that flows from left to right (or vice versa) and dumps into an existing internal vertical overflow? I've got a 65 gal tank with a single vertical corner overflow. I want a horizontal overflow but can't drain and drill the tank. I'd really appreciate any guidance from anyone who's tried this before I take the plunge.
Thanks,
Robert
 

headshrink

New member
Great idea. I would think two strips of acrylic siliconed to the top back of the tank....would need to punch a hole into your existing overflow. I would think making the teeth would be the toughest part..... maybe you could used one of those guides for making box joints with the router....
 

headshrink

New member
<a href=showthread.php?s=&postid=8073442#post8073442 target=_blank>Originally posted</a> by RobertK
Yes, I'm not sure how to make the teeth. What sort of guide are you talking about?

You can check out thisDIY job, but I wouldn't run acrylic through on that blade.
You could also look at something like this. Although, the teeth may be too big.
The cheapest, however, and possibly the best for your application would be Melev's tooth jig.

Good luck!
 

RobertK

Premium Member
Thanks for the suggestions and links. (you just like the first one because the blades are made by Freud, right?) I agree the third one is the only one I could even consider, except I don't own a router or a table saw. I'll have to chew it over. Maybe my local plastics shop can do it for me.
Thanks,
Robert
 

brackishdude

New member
No teeth, just weir. Weldon a piece of plexi to the inside of your vert OF to close those teeth.

Check out the calfo threads over the last few days. Here's more http://reefcentral.com/forums/showthread.php?s=&threadid=619976

The interface between the existing box and the calfo would be the tough part, getting flush and sealing it. The water can flow through a drilled hole at any level (i.e. no "over-the-top-flow needed).

Good luck and post pics.
 

RobertK

Premium Member
Yes, I've been reading that thread and all the others I can find on overflows. I've seen the trend away from using teeth, but I've been having trouble figuring out how to do it without them.

Part of the problem is that the tank has euro braces sticking out 3-1/2" from all four walls. I think the whole contraption needs to be removable so I can clean it - I won't be able to get down into it from the top due to the brace. I might have to rig up a clamp or tie of some sort to hold it onto the tank from the top.

I was thinking of cutting out one or more of the teeth rather than sealing them off. Also, I presume that I'll have to make it slightly lower on one side to make the water flow from left to right.

Keep those ideas coming! I'll post some pics when I can.

Thanks,
Robert
 

RobertK

Premium Member
Here is a picture of my overflow. It is 5" square and the adjacent glass top brace is 3.5" wide. The tank itself is only 15" wide. I will need to somehow attach the new horizontal overflow to the top brace so that I can remove it for cleaning, as the brace will prevent me from getting down into it from above. I will need to abandon the hole in the brace for the return line and run the return in front of the new overflow. I am thinking I might build some brackets out of acrylic so I can slide the overflow on and off the brace, then clamp it to the side wall of the old overflow - that way I won't need to use any silicone or glue. What do you think?

126overflow.jpg
 

Jasen Hicks

Premium Member
Robert, from the other post...

Id use ABS as it is easier to silicone to glass. I have heard of horror stories of using silicone on acrylic and it not holding worth a beans.

Jasen
 

RobertK

Premium Member
Rendos,
Looks like you have the gutter guard glued to the inside of an acrylic overflow. Yes? What kind of glue?
Thanks,
RK
 

RobertK

Premium Member
OK, so I still could use some help designing this thing. What I've deciced to do is build a trough 3.5' long (the width of the top opening on the tank) that is the same width as the glass top brace (3") or less, with brackets that will clamp it onto the brace. I'll also clamp it onto the existing overflow, that way the whole thing will be removable for cleaning and I won't need to glue/silicone it in place. I still haven't decided about the teeth and about how to tap into the existing overflow.

Here are my questions:
1 - what dimensions of the trough would be needed to handle about 700 GPH? The smaller the better so as not to take up too much tank space.

2 - How much of a drop is needed from left to right to ensure that the water flows steadily through the new trough into the existing vertical overflow?

3 - How thick do you think the sheet of water will be as it spills over into the trough?

Thanks!

Robert
 
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