Originally Posted by
lilredwuck http:///forum/post/3194715
I have a 90 gallon tank 48 x 18 x 24. Drilling for two 1.5" bulkheads. I am putting them up top. What is a safe distance for drilling them, from each other or the edges. I also plan on a long horizontal overflow box. What size should I make the box? Is there a certain amount of surface skimming it should do. Was looking for a longer, shallow, not deep overflow box. Still can't decide where to place the drains and returns. Three ideas here, crude but quick.
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The general rule of thumb for drilling bulkheads is,you want to stay at least the diameter of the drill bit away from the outer edge.For example if you have a 1.25" hole saw bit you are going to want to stay 1-1/4 " away from the edge.
As for the size of the overflow itself their are many variations to the dimensions to make your overflow run efficiently.here are two places i would start to research your project .
The first one is if your really want to do a complete DIY.
http://www.beananimal.com/projects/silent-and-fail-safe-aquarium-overflow-system.aspx
Its really a nice system and beananimal is always eager to help.
The other is more plug and play but cost efficient and easy to do.
http://www.glass-holes.com/Complete-Overflow-Kits_c3.htm
Have fun
