How safe are external overflow boxes?

[nekomi]

Hi everybody,

I have an empty Oceanic 37g cube (24" x 18" x 21") that I want to add an overflow to. I've considered several designs - classic internal overflow box, overflow box running the full length of the tank along the back wall, and external overflow box added to the back exterior of the tank.

In the end, the external overflow boxes are my favorite for their clean appearance from the front of the tank. I've read Tunjee's thread (http://reefcentral.com/forums/showthread.php?s=&threadid=271539) on RC in which he did the same thing, but then later in the thread, others chimed in and reported that their tanks cracked/broke after installing the overflow box and running it for awhile.

So does anyone have an opinion on this kind of overflow? My tank is only 24" long, and it seems that it's only larger tanks that cracked, but I'm still worried because my tank is 18" front-to-back, with no brace. Should I install two smaller external overflow boxes in the corners instead?

Thanks for any tips, I appreciate it!

 

[LA-Lawman]

as long as you have a "u" tube design... not a CPR design I would say no problems... some good companys with good overflows...

www.hurricanefilters.com
www.lifereef.com

can't think of any else... someone will chime in...

 

[nekomi]

Actually, I meant the kind of external overflow boxes where you drill the back of your tank, then silicone the overflow box to the outside of the tank instead of the inside. The thread I linked to in my first post has an example.

Thanks for the input, though

 

[Rob Top]

What's the point? Save some space insid ethe tank. Really the time to do that much cutting, when the reality is you could crack the glass when making your last cut. If you are cutting the tank, just pop a hole in t, add a bulk head and go. If you are that concerned about the space issue inside your tank, find some odd jobs to do for the time it would take to cut the glas like that and buy a bigger tank. Just my thoughts though.

 

[nekomi]

Well, I thought it was a neat idea, at least... :?

In any case, I was going to have the tank cut professionally, so time spent isn't an issue. I think I'm going to go with this design after seeing someone else's 37 drilled with the same configuration.

 

[magicman76]

I dont understand why they use the external applied box instead of putting a durso strait on the bulkhead to the tank and pluming it down to the sump.. I like the "calfo" overflow idea, the one with the internal box that goes all the way across the back of the tank.. seems to me that it would work really well at getting the surfase scum water to the skimmer in the sump..

 

[LA-Lawman]

i bet the tank is tempered and then u r up a creek with no paddle. I would save the money. it is better spent on the external overflow. if it isn't drilled already then don't do it. i have cracked too many tanks during my DIY stuff.

there are some great companies that make good overflow boxes... less drama...

if they break the tank thy will not replace it and you also void whatever warranty is still left on it.

let us know what you do and take pictures. we are all visual people

 

[magicman76]

tip from wetmedia..
two pair of polirized sunglasses show a pattern in the tempered glass when you twist one on one side and look through them both with one on the other side of the glass.. you can test it out on your car's windsheild to see what that patten is suppose to look like.. just a side note..
if the glass doesnt have the pattern.. you can drill it..

 

[smontanus]

I did this for my 10g and haven't had a single problem. The tanks acrylic though. I agree with magicman76 if your tanks glass, not familiar with Oceanic. With acrylic its easy and worth it on a nano I think. I thought about the durso thru the bottom but wanted as clean a tank area as possible. I wouldn't trust any bonding to glass either, acrylic can be solvent welded.

 

[magicman76]

its best to use glass on glass, silicone makes a molecular bond to glass therefore its safe to build the interal overflow/weir with glass if the tank is glass.. HTH
glass glass glass.. man.. hope that want to reduntant.. lol