Bulkhead Size? Drilling tank soon

[adamRS80]

I'm planning on getting my tank drilled and I'm about to order my pump, and all my fittings. My tank is an Oceanic 46 gallon. It's not the bowfront, but it's 24 x 18 x 24...basically half of a 90gal. Anyways I'll be using a Mag 9.5 and I wasn't sure how big my bulkheads needed to be for both supply and return. I was planning on setting it up like the small 30 gal cube at CB pets. Two bulkheads with screens near the corners for the overflows and one in the middle for return. How large do they need to be? Is that pump too big? I have a Mag 12 but I figured that might be too large for this tank. Thanks for the help. Take care.

adam

[duc]

I'm no expert but I just did the exact setup you are talking about with a 125. Here is what I found out:
I used a Mag 9.5 which is to powerful so I had to add a valve and cut back the flow. Why I had to do that is because I used 1" bulkheads, I wanted to use 2" but could not find anyone with a 2 1/4 bit. I would recommend no less than a 1" and if you can go bigger it could not hurt. IMO they cannot be to big but they can be to small. If my tank wasn't up and running I would up-size mine to 1 1/4 or 1/2. As for the flow needed for Reef or FO I have no idea what the actual min is but can tell you from experience that 3/4 in return attached to a 9.5 is to much for two 1' drains.
Clif

[jlam]

I drilled my own 100 gallon tank using a 27mm bit which is about 1.063 inches. Now looking back I would have went with something a bit bigger maybe a 38mm which would be 1 1/2 inches. The reason is because with the 27 mm I had to force (2) 3/4 inch bulkheads into the holes which was very tight, right after the 3/4 bulkhead I did go to 1 1/2 inch pipes which I think might help. I was afraid that it would not be enough flow for my mag12 using a SCWD but it keeps up with the flow. Even with 1 side fully plugged it was able to keep up with the flow. I found that out when one of my nars. snails went into the pipe and would not come out. But if you go with 1 1/2 inch hole with 1 1/4 bulkhead it will run more silent, as well as room to upgrade to a bigger pump if needed. Not that you will need to upgrade a mag12 with a 46 gallon tank but IMO mag12 is just fine for a 46 gallon tank. The more flow the better. I am cycling my tank 20 times per hour and there are still some dead areas in the tank. Hope that helps!

[adamRS80]

So you drilled your own tank yourself? I have lots of drills but they're all handheld. Where did you get your drill bit? Did you just use a hand drill? Was is battery powered or highspeed electric? Let me know how you did it because I'd love to do it myself. I'm sure the bit would cost less than paying a store to drill 3 holes for me. I've seen it done a couple of times. Do you just putty around the hole and fill it with water, or is there some special liquid that needs to surround and cool the bit? Sorry for the stupid questions, I'm usually pretty good with DIY stuff but I've never attempted to drill my own tank.

[jlam]

I got my bit from this website: http://www.khue.com/dept/tool/dbits.htm. I had access to a drill press IMO thats the only way to go, because you can get even pressure. I have heard of people doing it with hand helded drills but I would not trust it. Make sure that the glass is not tempered, if it is it will shatter. Other than that yes, I went to the toy section and got some silly putty formed a dam with it and filled it with chilled water, does not need to be deep. To start a hole, begin by gently kissing the glass until clouding appears, increase the pressure and continue drilling. Throughout the drilling cycle, oscillate the drill up and down, decrease pressure near the finish. Also I like to use rubber clamps and clamp a piece of acrylic anything that can give it even pressure on the back side so you get cleaner holes. The key is to go slow, it took me 30-45 mins per hole.

JL

[adamRS80]

What kind of drill press did you use? One that accepts a typical handheld drill, or an actual drill press? I think I could buy the bit, and press for less than $60 which is about what it would cost for me to get somebody else to do it. I've seen so many Oceanic tanks drilled on the back that I'm sure it's not tempered. Every tank at Aquatic Warehouse is drilled this way and at least a couple are Oceanics.

[ratboy]

Ive drilled tanks before as well and the only additional advice Id add to jlam's is I use antifreeze to keep the glass from heating up. Ive even drilled tempered before (~ 80% success rate). Many cheaper tanks use tempered glass on the bottom so thats why you see alot of tanks back drilled.

[adamRS80]

Ratboy, Thanks for the information. I'll definitly try antifreeze. Did you use a drill press or just hand drill?

[ratboy]

drill press...

[jlam]

I used and actual drill press but I am sure that you could use anything that would allow you to apply even pressure. But if you have to buy more than the drill bit then might as well have someone do it because in there are several places in Austin/Round Rock area that will drill one for 20-30 dollars per hole. At the time I got my drill bit the cheapest I could find it done for was about 40 dollars a hole. Which is why I did it myself. Cost for a 1 1/2 inch drill bit will run you about 40.00 w/shipping unless you are going to be drilling more holes in the future might not be cost effective.

JL

[dan]

i would go with 1 1/2'' drain and 1'' return. on the return you could allways reduce it to 3/4''or 1/2''on the 1'' bulkhead. at least you have that option. most of the time the problem is water out not water in.

[adamRS80]

Another question I have is how far do I need to be away from the corners, and top of the tank. I guess the top would just be where I want the waterline, but is there a distance that I need to be from the corners for strength/stress reasons? If I can find a press, and bit I think I'm going to try and do it myself. I'd hate to locate the holes in such a way that my tank would not be safe, or could break for some reason. Any tips here?


Dan, thanks for the advice on the bulkhead size.

[alexwolf]

Adam, I have a drill press you can use if you like. You just have to bring the tank over.

[jlam]

I have been told to do it at least 4 inches away from the top or side. So I did mine 4 inches down and 6 inches in and made a my overflows out of acrylic. I stole the design from this website: http://www.reef-eden.com/DIY%202%20.htm and it works well as a surface skimmer.