Anyone have DYI Overflow Box Plan?

[dawgwe1]

Looking at possibly making my own overflow box for a 29 gallon tank. Does anyone have any plans already done up they can post?

Thanks

 

[DonW]

You really dont need plans its just a box with teeth and a hole. What design are you looknig for. A hang on box or a walled in overflow?

Don

 

[dawgwe1]

Hang on style to overflow down to a sump tank

 

[cptbjorn]

HOB continuous siphon overflows take a whole lot of acrylic skills, there's plans on melevsreef if you want to check them out. It is much easier and cleaner looking to just drill the tank...

 

[dawgwe1]

I am still on the fence regarding drilling. It is only a 29 gallon tank and I am guessing I would need to drill 3" to 4" below the lip to make sure the glass did not break and that would lower the volume of the tank to the bottom of the holes.

 

[DonW]

I am still on the fence regarding drilling. It is only a 29 gallon tank and I am guessing I would need to drill 3" to 4" below the lip to make sure the glass did not break and that would lower the volume of the tank to the bottom of the holes.

The tank volume remains the same. Water level is just above the tooth opening. Take a look at the one glass holes sells. If this is what you want and still want to do it yourself I'm sure we can come up with a plan.

Don

 

[dawgwe1]

Will do...

 

[cptbjorn]

When you drill the tank then typically you silicone in an overflow box to put the water level back up above the bottom of the rim. You can buy the boxes pre-made, but I always just cut a sheet of 1/4" acrylic and take a propane torch and bend it around a 2x4 or 2x6 that I've rounded the edges off with a 1/2" radius bit. Here's what I mean:

 

[dawgwe1]

Thanks for the diagram - really helps. Do you normall just drill one hole for the water to go out and then have your return plumbed over the lip and back in the tank like a canister filter or do you drill a second hole for the return?

 

[cptbjorn]

I like to use what is called a "herbie" drain setup, where you have to drill two holes and have two drains. If you drill the back glass then you drill one lower than the other, and the lower drain is just a siphon with a ball valve on it that is the "main" drain, and then you have a second "backup" drain above it. You set the ball valve so that normally all of the water goes through the lower drain, but if it gets clogged and the level rises in the overflow the excess water can go through the backup. For a 29g 3/4" would be a good lower drain and 1" would be a good upper drain.

What the herbie setup buys you is some extra protection if the drain clogs and it is also completely silent in operation, there is no "hot tub" noise like there is with other overflow methods that have air going down the drain pipe and also you only get a small number of microbubbles to worry about in your sump. There are whole big pages and threads all over the web about the herbie drain you can check out, they explain it better than I can and with better pics.

On top of the two drain holes I like to drill two returns but you can always do those over the top if you want. Here's what the hole layout looks like on a tank I made, sadly I don't have any pics after I siliconed in the overflow:

 

[dawgwe1]

Thanks for the picture and explanation. One more question - once you get the pumps going - is the water level adjusted in the overflow so it is between the two drain holes? I looked at some 'herbie' type set ups last night but they were showing standpipes in the tank. I like your set up much better.