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Bulkhead/overflow what do I need to know?

8K views 20 replies 6 participants last post by  Michel 60 
#1 ·
I want to build another 5.5 gallon custom tank like the one I built for my mom. The difference will be that I want mine filtered and heated with a 5.5g (standard) sump/refugium.

My idea was to have the bottom glass drilled in a back corner and install a bulkhead with a 1/2" diameter clear acrylic tube going all the way up to about 1/2" from the top of the tank. The underside would be attached to a tube that drains into the refugium. There would then be a pump in the sump side of the sump/refugium that would pump the water back up into the tank through an acrylic Lily pipe that I will attempt to make myself.

So basically the water in the tank would only fill to the top of the acrylic pipe, then drain down the pipe into the sump, get filter, and then sent back up to the tank.

I want to do this rather than an overflow box as I feel its more attractive, easier to hide, and easier to install (I hope).

My questions then are:

1.) How far from the corner of the bottom glass should I drill the hole so that the glass remains structurally sound?

2.) What kind of plumbing fittings do I need to attach a 1/2" OD acrylic pipe into a bulkhead?

3.) What diameter will the hole have to be to accommodate the 1/2" pipe and the fittings?

Thanks for the input!
 
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#2 ·
My questions then are:

1.) How far from the corner of the bottom glass should I drill the hole so that the glass remains structurally sound?

2.) What kind of plumbing fittings do I need to attach a 1/2" OD acrylic pipe into a bulkhead?

3.) What diameter will the hole have to be to accommodate the 1/2" pipe and the fittings?

Thanks for the input!
Answer to 1. This distance is equal or greater than the diameter of the hole determined in number three (3) below. For example should you need a 2" hole the edge of the hole would need to be 2" from the side of the tank; and for a e placed in a corner that means both the back and the end.

Answer to 2. Start with a standard bulkhead fitting if you can find one that small. You may be able to use a heavy duty PVC cement to get the job done. Most PVC is white but you can use Krylon sry paint flat black to cover that. Be careful when gluing an Bob's your Uncle.

Answer to 3. Once you have found your fitting in #2 above the diameter of the hole required maybe self explanitory.

Hope this helps.

Best wishes,
Wes
 
#3 ·
So long as none of the fittings are higher than 1" from the bottom of the tank, they will be covered by the substrate, and I'm going to have plants in front of the tube anyway.

Also I thought of another question. Will 1/2" diameter tube allow enough water out to keep up with the water being pumped in through another 1/2" diameter tube? I'd rather not have to get two sizes of acrylic, but it's fairly cheap, and it would probably cost the same to ship both together as just one alone, so it's not a huge issue. Maybe I will go to the hardware store and see what I can find for bulkhead fittings and decide on my tube size based on that.
 
#4 ·
So long as none of the fittings are higher than 1" from the bottom of the tank, they will be covered by the substrate, and I'm going to have plants in front of the tube anyway.

Also I thought of another question. Will 1/2" diameter tube allow enough water out to keep up with the water being pumped in through another 1/2" diameter tube? I'd rather not have to get two sizes of acrylic, but it's fairly cheap, and it would probably cost the same to ship both together as just one alone, so it's not a huge issue. Maybe I will go to the hardware store and see what I can find for bulkhead fittings and decide on my tube size based on that.
Are you real good in physics? There is a solution to the question; I just cannot get my head around the math right now. Look to: http://www.phy.cmich.edu/people/andy/physics110/book/chapters/chapter9.htm

But that's the long answer. I'm sure there is someone that can answer that more directly and difinatively. :)

Best wishes,
Wes
 
#5 ·
That's way more math than I am capable of, lol.

I just went to home depot and looked at their bulkhead fittings, they DO have a 1/2" one, and a 3/4" one. They are threaded on the inside though. I'm going to be putting a non-threaded tube into it. How do I deal with that? I was thinking I could just put a good layer of silicone on the threads and put the tube in and put another ring of silicone around the top?
 
#6 ·
That's way more math than I am capable of, lol.

I just went to home depot and looked at their bulkhead fittings, they DO have a 1/2" one, and a 3/4" one. They are threaded on the inside though. I'm going to be putting a non-threaded tube into it. How do I deal with that? I was thinking I could just put a good layer of silicone on the threads and put the tube in and put another ring of silicone around the top?
Me too :) lol
Way to much math ... I a firm believer in calculaters ... which button is the flow button?:confused:

Next time you go to home depot see if they have a fitting that goes from that threaded part which is most likely a pipe thread (tappered) to a slip fitting (straight) that can be glued. I would not trust the silicon over the long term and have it leak. :eek:

BTW It's good your planning this out a little in advance ... some rush right in and ... "Help I have a leak now what?" or worse, "My tank overflowed why?

Best wishes,
Wes
 
#7 ·
Thanks alot for all your replies. I always like to plan stuff out ahead of time. This project is going to be very slow, as I have limited funds, so I'll be getting a piece here and a piece there and doing as much myself as possible.

I went to Lowes and looked for a bulkhead and they did not have any, but I did notice they had the type of fitting you are talking about to go from threads to a slip, so I can do that. I also found Bulkheads online here http://www.diamondbitsusa.com/index...art&page=shop.browse&category_id=13&Itemid=57
as well as the diamond coated hole drill needed. They recommend a 1 1/2" hole drill for a 3/4" pipe though! That seems really big o_O Is the bulkhead really 3/8" thick on the walls?
 
#8 ·
Have you ever heard an open standpipe? How much do you enjoy the sound of a perpetually running toilet? Also, I wouldn't run a bulkhead smaller than 1" on any tank for fear of flooding.

A Mame style overflow (I've seen DIY versions) or even standard overflow box would be my choice. You can even build one out of clear material, a la ADA.



 
#9 ·
The tank I am putting this on is 30" long, by 8" tall, by 6" deep. An overflow box would be incredibly huge and bulky, even made of clear material. I don't mind the sound of running water, and I almost always have a fan or the TV going anyway, since I can't sleep without white noise, even in the winter.

My plan is to have nothing in the tank for equipment but a clear acrylic lily pipe or spray bar as an outflow, and a glass CO2 bell diffuser.

The website I linked above said a 1/2" bulkhead will work for a pump 150gph or less, and a 3/4" bulkhead will work for 360 gph or less. I'll probably be using a 200gph or less pump. Likely 160, actually, since I already have one on another tank and it lifts the water a foot or so with plenty of force to spare.
 
#13 ·
The website I linked above said a 1/2" bulkhead will work for a pump 150gph or less, and a 3/4" bulkhead will work for 360 gph or less. I'll probably be using a 200gph or less pump. Likely 160, actually, since I already have one on another tank and it lifts the water a foot or so with plenty of force to spare.

If the sound doesn't bug you, I am envious.

The reason I suggested a larger bulkhead is the ease of which a snail, dead fish, or plant matter can clog an open 1/2" or 3/4" pipe. If that happens, there's water on the floor and in your eyes.
 
#11 ·
I should add that I like this idea. I like it a lot. If I'm understanding you correctly, you'll end up with something that looks an awful lot like the visible parts of an undergravel filter, which are quite visually unobtrusive. The idea alone is worthy of a "whiz-bang neato!" :)
 
#12 ·
The tank is one I'm building myself, so I'm positive the glass is not tempered. Thanks, I will check out the sites you listed.

And that is exactly what I am going for, the clear tube that goes up to the top for an under ground filter, only without a power head on top.
 
#14 ·
What I am thinking I may do is use the acrylic tubing that I will already be attempting to bend in order to make the lily pipe/spray bar only in a larger diameter and bend it into a suction Mame style overflow as was posted above.

The only question I have about that is what are all those other pipes and tubes for coming off of the main largest diameter tube that is the actual overflow and are they important?

Edit: After looking at more pictures of the Mame overflow from other directions, I understand that the other little tube is the outflow.

I think it would be too expensive/difficult to make out of the acrylic, as I would have to get clear PVC fittings which are not cheap.

So I am then left with my original idea of essentially a noisy drain.

Edit #2 Hmm...If I used normal PVC fittings and painted them a bright white and kept them on the side of the tank instead of on the back, and put a bunch of plants in front of it, I might be able to live with doing it like this only using the clear acrylic for the part that is actually IN the tank.

http://www.nano-reef.com/forums/index.php?showtopic=254404
 
#15 ·
The only question I have about that is what are all those other pipes and tubes for coming off of the main largest diameter tube that is the actual overflow and are they important?


Remember that the middle tube is the return. It is connected to the intake so that the overflow will restart automagically after a loss of power. When the power kicks back in for the return pump, that tube creates a venturi which pulls water over the edge. Cool, huh?

There are a couple ways to do this. For simplicity, I've also heard of other people skipping this step and instead using a [good] check valve.

 
#16 ·
How would a check valve work?
 
#19 ·
They have bulkheads in with all the other PVC fittings and vynil tubing. I nearly overlooked them. But they don't look quite the same as the ones I found that are made for aquariums, so they may or may not work.

I think I'm going to do a mock up of my original drain idea and see just how loud it really is, then make my decision from there. I really love the way it would end up looking, and the simplicity of construction, as well as how easy it would be to hide behind some plants.

Also, I just tried out my bathroom drain in my sink, and it is completely silent other than the water splashing against the inside corrugations of the pipe (I have the plastic bendy pipe going down into my U-bend, the kind that looks like a bendy straw)
 
#20 ·
I HAVE THE SOLUTION!

I just need to run a length of airline tubing down the drain until I find that sweet spot where it makes the drain silent. Works just like in a houses plumbing, there is a pipe that goes up to the roof that allows air into the system. I just have to keep the top of the airline tubing above the water line. :D
 
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