Overflow slots

[blastprimo]

I am making an acrylic internal overflow for my 20H and I am trying to figure out what the normal spacing on overflow slots is and the size of these slots would be (width and depth).

This is probably a dumb question, but will the main tank level stay at the level of the bottom of the slots or would it be above that? I am assuming it would be above that and all of that level is controlable with the return pump?

Please, any help would be appreciated

 

[skipm]

I have seen them made two different ways, the first is to have 3/16" wide slots with a 3/16" space between them and the seconde was 1/4" wide slots (form a tablesaw blade) also with about 3/16" spacing. HTH, Skip

 

[blastprimo]

Thank you for the reply. I ended up cutting them this morning. I went with 1/4" slots that are about 3/8" apart. I didn't feel comfortable cutting them too close together. Here is a quick pic:

 

[distantfire]

When you get a chance check out (project external glass overflow) you can find it on the diy page of reef central. Enjoy....

 

[cich1]

i'm just finishing up a external overflow on a 29g tank

 

[distantfire]

Nice move, are you going to go with 2 1inch bulkheads or just 1 on your 29gal. And how big of a sump/fuge do you have for it. And what size return pump are you going to use? Sorry for all the questions, I'm just curious. Because I'm doing the same thing to a 15gal. long aga. And I have a 10gal. aga for my sump/fuge.

 

[Phischy]

How high the water will get will depend on the volume of water that can flow through the area you've cut depending on how many gph the sump pump will be returning. To my knowledge it's a trail and error type thing. On my overflow it is well above the grooves I've cut, it can't pass through 400gph so it goes through, then up and over. Some snails have found their way below but no biggie. I've got a 2" drain pipe.

 

[blastprimo]

Thank you for the answer on the water height. That is kind of what I thought and I may end up buying a new return pump if i get some extra cash one of these days. I am planning on using the rio 1700 that was on my 75 gallon and I may have to throttle it back with a ball valve a little. We'll see. Tonight, I do my second test to make sure that the overflow is sealed to the walls.

As for the external overflow, I looked at it and decided that I didn't want to deal with that much work. All I had to do on mine was buy the tank drilled from AGA and work with a small sheet of 1/4" black acrylic. It looked really neat but just took a little more work then I wanted to do. I also got a little scared after seeing a few of the tanks that broke after attempting the slotting for the external overflows.