[Ratpack]

Well, I have the opportunity to build my own tank and I think I am going to do it. The size is a 120 gal (4x2x2). I have arranged to get the glass which is 1/2" tempered all sides and bottom. Can't beat $54 for all the glass. And since they are tempering the bottom for me, they are also going to drill the holes I need before tempering it. So that brings me to my question. How many holes, what sizes and where? I can also have some in the back as well. My thoughts are one hole in each corner of the bottom so I can have twin overflows and a hole in the back near the top corners for the returns. Thoughts?

If all fails, I am out very little, but if I pull it together, I may have myself one very affordable tank.

[Samper]

What kind of flow are you going to put through it? My thoughts on this are that the overflow holes need to be larger than the imput holes so that they are always going to be able to handle whatever you throw at them. Personally I'd do 6 1" holes in the back. 4 of them on a closed loop and two of them for the return from the sump. For the drains in the bottom of the overflow 2 2" bulkheads should work. As far as hole sizes go I'm not sure at this point and don't have the time to look them up. Seems like I always have a hard time finding them when I need them though. Good luck.
I'd use an external sequence pump for the return from the sump and a mag 18 on a closed loop behind the display. I'd put them on true union ball valves so you can regulate flow if you need to and remove them easily for cleaning. At any rate that will be enough flow for sure. I'd also use threaded bulkheads this way on the intakes for the closed loop you can attach strainers and for the output you can use modular hose and aim the flow where it is needed.

[Ratpack]

Thanks Samper. I found this on Drs Foster and Smith so I can use the diameter they recommend:

SizeHole Dia.1/2"1-1/8"1"1-3/4"1-1/2"2-3/8"2"3"

As far as the closed loop, I am sure the wife will put a tight rein on the spending for a new tank so that might have to come later, but I do agree that the holes should be there already. Just wondering what I could do in the mean time of getting a pump, I guess plumb them down into the stand and cap them off for later use. Also where are the holes for a CL usually placed?