DIY overflow any help?

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you're on the right track!

you don't need the extra chamber on your inside "box"

and the chamber "baffle" or weir actually on the outside box needs to be "taller" - this is what sets your tank's water level.

it also prevents the siphon from breaking during water changes and the like

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depending on how many GPH you want to flow, you may need 2 or 3 siphon tubes and drains ... I had a calculator for this at one time- i'll try to dig it up for you

going great - keep it up!
 
here's the calc

http://reefcentral.com/calc/drain.php

I wish it was programmed to have a threshold to say you need 2 drains at 1.5 inches, rather than say you need a drain that is at least 1.92 inches

but it helps

just round up and divide, and then round up to the closest pipe size and you should be OK
 
almost there!

you have the drain and siphon sizes reverse, siphon should be bigger than the drain.

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I know you're planning teeth, but they're hard to draw!

about the teeth:

you will want to cut straining "teeth" into your internal box (1/4 inch is a popular size, spaced 1/4 inch apart), you want the bottom of the "teeth" to be at or below the same level as your outside weir ... this will ensure most efficient operation and minimize build up of debris inside the overflow

the tops of the teeth should come out of the water somewhat as well, to help prevent debris from "falling over" the edge and getting stuck in a siphon
 
oh, 1 more thing ... that 1" wide "space" between your inside and outside box is too much

measure the width of your tank wall, and then add like 1/8th" for fudge factor and use that as your spacing

safe bet would be at most 1/2" space
 
got an email from craftics - my glue should be here on 8/5

can't wait for it to arrive so I can weld together mine and test it out

btw, to be on the safe side, I ordered three viscosities of Weld On ... #4 which is water-like, #16 which is a thin gel and #40 which is a 2 part epoxy like material ... The #40 meets some sort of DoD spec for strength and durability, so I'll probably use it to join my inner and outer boxes.

dusty - I also plan to have 2 nylon screws going through the part that hangs on the tank, pressing down onto the lip of the tank, so I can raise and lower the box in relation to the tank, hopefully to give me a little water level adjustment ability.
 
and the chamber "baffle" or weir actually on the outside box needs to be "taller" - this is what sets your tank's water level.

I saw this earlier in the posts and I have to disagree with this... Most overflows have the basket inside the tank determine the water level. The siphon tube then sits over the tank, and in the outer box, the bulkhead and tube should raise above the siphon U-tube. this will create the lock and thus when the power goes out, the overflow will not lose the siphon. The outside of all the overflows I have seen for externals, have been at least 4" below water level...This in turn, creates somewhat of a pull for the water to continue flowing... :mrgreen:

Also, the outer box doesn't really need a baffle at all..
 
I think it depends on the design used

many of the DIY designs I have seen use an external weir / baffle, to maintain the siphon while doing maintence on the drain, as well as to help control water level.

I believe the CPR overflow as well as the Life Reef use a weir in the external box as well

I imagine using the inside box solely to set water level is OK too - to each their own :)
 
(y) that's great to hear!

if you get everything and it's really cut nice / fits together well - be sure to write up a quick review for the gen. retailers section - I'm sure others in texas would like to know about a aquaria friendly dealer such as the one you found.

:!: :!: this thought just occured to me

when you orderd your pieces, you did include the width of the paneling in your measurements for the bottom pieces right?

like your overflow being built from 1/8th stock, so you need the bottom to be 1/4" longer and wider so the "walls" can be glued onto it

same thing for your sump - with 1/4" stock you need an extra 1/2" inches length and width on the bottom to accomdate the walls!
 
The inside overflow box. Do you plan on having it have slits or fingers to kind of strain the water going into the box?

Will the inside box be adjustable so you can make minor adjustments to the inside tank water height?
 
Most overflows that hang on the back have a slit cut into the inside box. this slit runs verticle and there is a hole and stainless steel or nylon screw and nut that fit in a hole on the hang on portion of the overflow.

You can losen the nut and slightly rase and lower the intank portion of the overflow to have a direct effect on water level.
 
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