Project External Glass Overflow

i put a beed of siiconed along the edge placed it on the other piece & wiped off what came out, that was for the box then i just did the same when i put the box on the tank.
 
How are you guys coming up with flow rates and what what sizes to cut?? I have a 150 that is running 1300-1500 gph. I am possibly interested in doing this but not sure how big I would need to make the cuts. I would like to do 2 overflows (one on each side) Thanks
 
There is a calculator here on RC's home page. It will give you the drain size needed and linear inches for the overflow.
 
tunjee...can you tell me a little about your light? I already stole your idea on drilling tanks. I drilled my 29 similar to how yours is drilled.

Mike
 
I ended up leaving the bracing off, came out pretty decent though.

tank_mod_overflow.jpg
 
Looks good Bishop! Hope it doesn't crack like MacnReef's. I'm hoping doesn't as well. I wonder if placing a bead of silicon over the cut would help in keeping it from cracking at all? Hmmm.
 
That sucks macnreef.... If mine does, it will give me an excuse to build a new tank.. heh

impur, I doubt the bead of Si will help much...
 
Why is everyone making an overflow bow instead of just cutting a circle and just putting a bulkhead directly on the tank
 
kilo said:
Why is everyone making an overflow bow instead of just cutting a circle and just putting a bulkhead directly on the tank

Probably because a bulkhead in the back wall doesn't do as good a job of skimming the top layer of water. JMO.

- Chad
 
Have a little faith in yourself :) I was afraid of screwing it up too, but if you use a dremel with a diamond bit, use more water than you think is necessary, and go slowly, you'll do fine.

I've never done anything like this before and I was very pleased with the results.
 
I've come up with a modified version of this. Glass is cut, progress on new tank slow, so not complete yet (we have triplets, 4 mos old, so time is sparse. . .)

I originally drilled two 1-3/4" holes in the high back wall of the tank intending to put an internal overflow across the back wall exiting through two 1" bulkheads (hence the needed 1-3/4" holes)

Two problems: flow limited by 2 gravity-driven 1" returns, and making room for the downturned street elbow on the tank side required the overflow to protrude into the tank too far. I wanted only 1" or so. I had intended to put durso tees on the outside.

Based on ideas from this thread, I decided instead to simply leave the 1-3/4" holes, put a 4" tall x 1" deep weir style overflow along the back wall of the tank. I then will have 2 overflow boxes on the outside of the tank centered on each of the drilled holes, styled similiarly to what you are all using here. Each esternal overflow box will have a pair of 1" retruns using stockman standpipes.

This compromise will greatly increase the flow capacity and reduce the projection of the internal overflow into the tank!
 
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