Assembly Diagram

Congratulations on purchasing a Glass-Holes.com overflow. If you are considering buying one, then please read through these instructions and for more information on what makes these overflows so special please visit http://www.momsfishsupply.com/whyglassholes.html .  Our goal is to give you the best overflow for your tank possible at a reasonable price.  Our products are 100% satisfaction guaranteed, so if you have any problems please contact us. We will resolve the problem or promptly refund your money.
            
Placement
           The first thing to do when you have received your overflow is to decide where you want it to be placed in your tank.  Where it goes in your tank is purely up to your taste, we just have some height recommendations. With our toothless overflows we recommend 1 ¼" down from the rim of your tank (the plastic that the lid would sit on, not the actual top of the tank).  The exception to this will be the nano overflow, in which case we recommend ¾".  On our toothed models we recommend 1" down from this rim.  Both these placements will allow you a safety margin in water level and yet assure that your water level will be above the trim level for looks (assuming you are following flow recommendations, if you want to flow more or less please contact us concerning placement). One other point on placement of the box, when placing your box do yourself a favor and leave enough room on the side for your magnet cleaner of  choice. Once you have your desired placement you will need a nut off one of the bulkheads to mark where your hole(s) will go. You will want the nut placed lower than the middle of the overflow, but keep in mind that the bottom of the overflow is ¼" thick, so the bottom edge of the bulkhead nut must be at least ¼" from the bottom of the overflow.  Two things to keep in mind now while placing sites for hole(s).  First, you want the hole(s) to be at least one hole diameter away from any edge of the glass.  If you are drilling a 2 3/8" hole for a 1 ½" bulkhead, then your hole needs to be 2 3/8" away from any  edge. Also, same thing applies to hole placement in regards to other holes, they should be at least one hole diameter away from each other.  
 
Drilling
           Once you have your hole placement decided, you are ready to drill your glass (if you have a acrylic tank you can skip this section).  You will want to lay the tank on its front to have the back laying horizontal.  Be sure to protect the front of your tank from scratching. You will also want to be sure to put something like a piece of cardboard inside the tank under where you are drilling, the plug you drill out will likely fall through and could possibly crack the front.  I want to note that we do not recommend drilling full tanks, although it has been done successfully.  Your next step will be to make yourself a little reservoir around the holes using plumbers putty or Play Dough-type materials.  Add some water in there and keep some in there while drilling to keep the bit cool and lubricated.  For your drill a drill with a clutch is best (a lot of cordless drills today have clutches, nobody ever uses the clutch).  Set your clutch to its lowest setting, this will cause the bit to stop if it binds.  A point must be made that drilling glass is actually grinding through glass, as such excessive pressure (more than a few pounds) should not be applied, let the bit do the work. Recommended speeds for drilling with the sizes we are dealing with here are 700-1000 rpm, just realize the faster you go the more your bit heats up and the fewer holes you will get out of it. Now you are ready to drill.  Starting the hole is the hardest part and it is not difficult. Hold the drill and bit at a 45 degree angle on the edge of the hole you have marked, drilling with one hand and guiding with the other.  Then you can start drilling.  As you drill it will make a grinding noise, you are literally grinding through it. As you start to get a groove forming on the edge start leveling your drill out as you drill.  Now your drill should be vertical and drilling the complete hole.  Keep your pressure light and water in the reservoir.   You will get to a point of seeing water start to seep through, which means you are close.  You will want to lighten up on any pressure here to minimize chip out on the other side.  In all likelihood you will have some chip out, this is ok (even the manufactured tanks with drilled holes do unless they finish the edge afterwards, which they very often don't).  If you have another hole then repeat the whole process.  Next you will need to put the box back in is spot in your tank and mark the holes you drilled in the tank on the back of the box. To drill the box you have two options. First you can use a regular holesaw of the correct size.  If you do not have a holesaw you can actually drill it using  the diamond coated holesaw (which actually leaves a superior hole in the acrylic).  If you choose option two it should be noted that the saw will want to walk so you will need to use the same angled tecnique you used with the glass to get it started. Drill at a slow enough pace as to not melt or bow the acrylic.  Now you have your holes drilled and only have to install your box now!
 
Box Installation
           Almost there, it will be well worth it.  You will want to take your street elbows (provided if you bought the full kit) and either Teflon tape or pvc solvent them into the internally threaded end of the bulkhead.  We recommend Teflon tape because it is removable and you will likely be able to get the bulkhead in farther.  Next you will want to get one of the bulkhead gaskets.  We recommend the use of silicone plumbers grease on the gaskets.  They will seal better without chafing or pinching as you tighten the bulkheads.  And yes, it is reef safe.  The first gasket will go on the bulkhead itself, then the bulkhead through the glass from the outside of the tank.  Next, you will take the second bulkhead gasket and put it on the bulkhead from the inside of the tank.  Now you can slip on your Glass-Holes.com overflow box and level it.  Then you can put the nut on the bulkhead from inside the overflow box.  Now tighten the nut, you can use the elbow you already installed in the bulkhead to tighten the nut, this is where you will really see a difference with the silicone plumbers grease.  A word of caution here: the elbow now hanging for your tank will allow you to put stresses on the glass that it would not otherwise have.  Please do not use this elbow as a handle to lift or drag the tank. The last thing to do is to insert the baffle(s) into the box.  They just slide in (they are snug) and sit on top of the bulkheads to keep noise to a minimum.  Now that you have your Glass-Holes.com overflow box installed, you can plumb it just like any other overflow.   Once your system is up and running you can slide the air vent in the street elbows outside the tank up and down to achieve the quietest operation.
 
Drilling any tank, glass or acrylic has inherent risks.  This is a do it yourself project, we are simply giving you a convenient place to get all the parts and materials in one stop and without having to buy all the special machinery.  Than being said, it is really very easy (easier than a MJ mod if you have ever done one).  Once you have done it you will jump at the chance to do it again.  If you have any problems or question please email Mike or Scott at info@glass-holes.com .  Thank you and best fishes, Mike Kirkman.

Assembly Diagram