Question about drilling holes?

sacsalt

New Member
Hi everyone
I have a question about drilling holes. I want to drill holes for the overflow that I want to make for my 90gal tank. I was wondering is it better to drill the back of the tank or the bottom corners or center. What diamieter should the hole be?
 

scsinet

Active Member
Almost every tank made 55g or over has tempered bottoms. You need to either confirm with the manufacturer if the bottom is not tempered, or don't bother and assume it is, and don't drill it.
I'd drill the back. Whether you use one or two overflows is more or less up to you, the tank is small enough that it shouldn't make much difference. 1" is a very common drain size, but frankly, I'd do 1.5" if you can. 1" might push 600gph if you are lucky, but it's not uncommon to see far less than that. 1.5" will handle well over 1000gph, so a single 1.5" back drilled overflow will handle over 10x turnover per hour.
 

gpkozmp

Member
I am wanting to drill my 100 gallon tank like it is in the picture with hole number 2. I am wanting to put it in the back, of course, but put it in the center and then from there I am going to be placing my rock around the overflow box.
Is this a good idea or since it is not drilled should I leave it alone?
Could I drill the bottom in this situation?
How many holes should I drill, 1 or 2?
 

bmkj02

Member
I like the idea of drilling the back. The reason is cause if a bulk head starts to leak you have to drain the tank if it drilled on the bottom. Same with drilling the back. I drilled mine high were the over flow is so if something happens it will only go down to that level. I drilled 2 x 1.5 openings in the top middle of my tank with one long not wide overflow.
There is a member right now asking for help on a leaking bulkhead on the bottom of the tank.
 

gpkozmp

Member
Originally Posted by bmkj02
http:///forum/post/3170347
I like the idea of drilling the back. The reason is cause if a bulk head starts to leak you have to drain the tank if it drilled on the bottom. Same with drilling the back. I drilled mine high were the over flow is so if something happens it will only go down to that level. I drilled 2 x 1.5 openings in the top middle of my tank with one long not wide overflow.
There is a member right now asking for help on a leaking bulkhead on the bottom of the tank.
So you said that you have drilled it in the center towards the top?
Do you have a picture?
Is this what it looks like?
 

davebrace5533

New Member
Originally Posted by gpkozmp
http:///forum/post/3170354
So you said that you have drilled it in the center towards the top?
Do you have a picture?
Is this what it looks like?
hey check my newest post "125gallon sump setups" i put a drawing of the system i built today. i put a 1500 gph overflow box in the center with the holes drilled int the back. i did two 2 1/2 inch holes it was way easy, just took a bit.
 

calbert0

Member
Nice plumbing, but i hope there are siphon breaks in those return lines that run to the bottom of the tank or you may be in some trouble.
 
E

eric b 125

Guest
i think i remember reading in another thread that the pvc at the bottom is for a CLS
 
E

eric b 125

Guest
gpkozmp: check out glass-holes dot com. i think it's safe to say that 99% of us that drill our tanks get the overflow kits from there. once you see the kits, and the instructional video, you'll see where to drill.
 

bmkj02

Member
Originally Posted by Eric B 125
http:///forum/post/3171366
gpkozmp: check out glass-holes dot com. i think it's safe to say that 99% of us that drill our tanks get the overflow kits from there. once you see the kits, and the instructional video, you'll see where to drill.
+1. This is where I got my kits from. After watching their video I was more confident in doing it myself. After I did it I felt like a pro.
 
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