Some basic plumbing questions

[canadian_srt4]

Looking to re-do some plumbing on my 120g tank to the sump.

There is a 2" hole (which seems overkill to me??) drilled on the back of the tank from the overflow.

Starting with the new bulkhead, which side should be on the inside of the overflow, and why? I am thinking I have to use the smooth side as I don't think I can fit the threaded side on the inside based on it being a corner overflow and limiting the room to work with. Also gasket on the inside or outside?

Pic of said bulkhead....
http://sphotos.ak.fbcdn.net/hphotos-ak-snc4/hs772.snc4/67232_10150301152845235_892985234_15417420_5831048_n.jpg



Now since I think the 2" piping will be overkill, plus its bulky and takes up way too much room under the tank, can I use adapters to downsize to smaller piping after the bulkhead? If so what is the smallest I should be going to?

I also do not have a lot of room between the wall and the back of the tank, so there pretty much needs to be a 90deg drop out the bulkhead. This makes me think its going to make everything noisy like it currently is. Are there any other solutions to keep it a bit quieter besides having to use a 90deg elbow right after the bulkhead? Or maybe something after the 90deg since I pretty much think I have no choice but to use it to start with?

Also since I am pretty much doing this to a fully stocked tank that has been up and running for about 1yr now, anything I should be concerned about or need to do in particular?

Pic of said tank….
http://sphotos.ak.fbcdn.net/hphotos-ak-ash2/hs340.ash2/61990_10150287984220235_892985234_15147011_3318715_n.jpg

May have some other questions as I go along....

[serpentman]

You can situation a bulkhead either way. Either way, the O-Ring has to be on the same side as the flange.

A "Bean" style overflow might be a good solution for this application:

http://reefcentral.com/forums/showthread.php?t=1310585

Also, you may want to research the "Herbie" method.

[jacksonpt]

Either way, the O-Ring has to be on the same side as the flange.
Is that right? I thought the o-ring had to be on the "water side"... if there is water on both sides, then 2 o-rings need to be used.

[Lynnmw1208]

the glass-holes overflow has 2 o-rings on their bulkheads for the overflow but i think it may be for extra safety. they put the smooth side on the outside.

[mcrist]

You can place a bulkhead either way but you should never use two o-rings. It is more common to place the flange on the water side since you typically don’t want to see the threads inside your tank.

[canadian_srt4]

awesome, that link was a good read as well, gave me a couple ideas.


What about downsizing piping after the 2" bulkhead? What size in the minimum I could get away with? I just don't like the idea of having to use 2" piping for everything, its too bulky.

[scbrooks87]

If the hole in the glass is 2", that doesnt mean you have 2" pipes... I think a 2" hole would fit a 1.25" bulkhead, or 1.5", not sure, but it wont be a 2" bulkhead.

That being said, you can use reducer bushing after the bulkhead to go with smaller pipe. I have a 1" bulkhead on my tank and used a reducer bushing to go down to 3/4" pipe for one of my lines I was running...

Anyways, the actually pipe size depends on how much flow you intend to put through the pipes... Figure that part out and people can recommend how big the pipe should be based on the design of your overflow.

Good luck!
-Scott

[Chris27]

Is the hole in the tank 2" in diameter or is the bulkhead set up to receive 2" plumbing? Typically, a 2" Sch 40 bulkhead will fit into a 3" hole.....

[canadian_srt4]

Sorry my bad, yes I meant its a 2" bulkhead. The actual hole drilled is 3".

My system is currently running 2" piping, which is why I hate it and want to go smaller if possible? So maybe I can go down to 1.5"?