Bulkheads?

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Pankt

Registered Member
Jul 13, 2009
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I've been trying to set up my 180 gallon tank for a little while now. And now i've been confused by bulkheads. I have no clue what size i need to buy. Of course I'm trying to find the largest inner diameter bulkhead as I can. The drilled hole in my overflow is exactly one and a half inches in diameter. When I look thru websites and they have the measurements they all seem to be measuring different areas and I don't know which one I'll need to fit perfectly. Can someone point me in the right direction for that?

Also if the outer diameter is 1 and 1/2in whats the inner useable diameter?
I think 1in PVC will fit into the bulkheads afterwards which might shorten the inner diameter again. Would two of these overflows provide enough flow to support a mag drive 18 pumping the water back in? (after about 5~6 feet of head i think it pumps around 1200 gph)
or Will the sump constantly be emptied out by the pump?

Thanks!
 
Pankt said:
I've been trying to set up my 180 gallon tank for a little while now. And now i've been confused by bulkheads. I have no clue what size i need to buy. Of course I'm trying to find the largest inner diameter bulkhead as I can. The drilled hole in my overflow is exactly one and a half inches in diameter. When I look thru websites and they have the measurements they all seem to be measuring different areas and I don't know which one I'll need to fit perfectly. Can someone point me in the right direction for that?

<< To be sure, measure the diameter of the hole that you already have, and you should find a bulkhead to match that size...

http://www.marineandreef.com/Aquarium_Plumbing_Bulkheads_Schedule_80_Grey_s/457.htm

>>

Also if the outer diameter is 1 and 1/2in whats the inner useable diameter?
I think 1in PVC will fit into the bulkheads afterwards which might shorten the inner diameter again. Would two of these overflows provide enough flow to support a mag drive 18 pumping the water back in? (after about 5~6 feet of head i think it pumps around 1200 gph)
or Will the sump constantly be emptied out by the pump?

<< Sounds a bit like your doing some guess work here, which you cant do. You need to correctly measure the holes, and this will give you th correct sized bulkheads. Remember, measure the internal diameter of the holes you have, which "should" then tell you what size bulkhead you need....which will then tell you what size pipe you need...

<< No experience with the Mag pump, so i'll leave that to someone else to comment on.. >>

Thanks!
Click to expand...


Added a few comments above...The website quoted is just there as an example...dont know what the company is like or price comparisons..
 
The holes will take 3/4" bulkhead fittings. 1200 gph is way too much for 2 of them. You'll need to cut that flow a whole bunch. Each fitting will only flow about 165 gph as a drain.
 
A standard bulkhead fitting for 1" PVC requires a 1.75" hole.
 
fsn77 said:
A standard bulkhead fitting for 1" PVC requires a 1.75" hole.
Click to expand...

So sorry i just want to confirm you mean 1" inner diameter PVC requires the 1.75"?

Would two of those be enough for ~1200 gph? or should I overshoot and go with.. maybe 2" hole just to be certain i'll be set?

Also If I decide to stick with these holes would it be possible to just skip the bulkhead and stick the PVC straight thru the holes then silicone the gaps?
I haven't seen anyone do this and again I'm assuming with good reason. possible stability issues?
Basically Im looking for anything that will maximize my flow without having to redrill but if I have no other options then I guess i'll go with that.
Also I rechecked my dimensions and i i think its around 160 gallons and tomorrow im picking up a 55 gallon tank to be the sump. the ~1200 gph pump would be good flow for it? around 7.5 turnovers not counting sump.

Thanks for all your help guys!!!!
 
1-1/2" hole = 3/4" SHC40 bulkhead. 1-5/8"=SCH80 Bulkhead.. believe me.. I found out this information the hard way.. ordering SCH80 bulkheads and only telling the tank builder I wanted to use 3/4" bulkheads and not specifying the hole size.
 
Just trying to cover all the bases I started looking at drill bits.
Would this be good for what I need? the glass is half inch thick and its rated to go thru 1.2 inches i think. Would the local home depot carry these drill bits? would rather pick it up instead of waiting for a week or two to ship from Hong kong.

http://cgi.ebay.com/50mm-2-Diamond-...m1c0bb10dbf&_trksid=p3286.c0.m14#ht_855wt_754

And will i have a problem drilling over a preexisting hole?
And also since im doing all this drilling Will i really need to drill the sump? i see alot of ppl do this but is it more beneficial than having the pipings just dump in water from over top?
Or is there another reason for it that Im not aware of?
 
You won't find them at HD. Never tried to drill over an existing hole but I've heard it can't be done. Seems to me that if you can keep the bit from wandering by using a guide and can keep the glass and bit wet enough it should work, but.... And no you don't need to drilll the sump unless you're using an external return pump.
 
Well Now I realize with school about to start and the massive weight(400lbs empty) of the tank I don't think I have the time to even consider redrilling these holes if it was possible. So i think I'll add one of those overflow boxes that hang on the back instead. I'm iffy on it and haven't done any research in the area since i assumed my overflows would be enough.

Any Opinions on the PF-1800 overflow box?
Anyone have one and have something to share about it? tips/suggestions?
http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=18358

I decided on that because I dunno how much flow I'll really get out of the box and my overflows.. I'm estimating around 1400 and I'd rather have it be bottle necked on my pump instead of the overflows so again I overshot(hopefully)
 
If you're going to go with a hang-on overflow box, your best bet is pretty much getting one from LifeReef (www.lifereef.com). They are called prefilter siphon boxes on their website. They're guaranteed to not lose siphon during a power outage.

The one you linked to may work just fine, as the U-tube style overflow boxes are more reliable, IMO, but I've never used one from the brand you linked to and do not know anyone that has.
 
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