Bulkhead Size

[EchoFish]

Hi all,

I will be having a tank special-ordered from Oceanic, with pre-drilled bulkheads. The thing is, I've never done anything like this before. The tank is 50-gallons, being plumbed to a sump just down the hall. Can someone help with bulkhead placement, size, and quantity?

* I know I'll need them in the upper-right corner, but how far down? 1/3? 1/4?

* What size should they be drilled to? 3/4 inch, 1 inch, etc?

* Do I need one or two? Obviously one for draining to the sump, but does the return come through a bulkhead or does it loop back up over the top (like a filter return)?

Thanks very much in advance!

 

[Entropy]

How much water you want to flow will determine the bulkhead size. I would have them install an overflow wall in the tank so the bulkheads and plumbing will be hidden, but that is up to you. You can run one hole for the drain and one for the return or just return over the back. Again that is up to you. You are less likely to leak with a return over the top since you will have one less bulkhead IMO.

 

[EchoFish]

The pump that I'm probably getting is rated at 300 GPH. What size would that make the bulkhead? And thanks for your help!

 

[Entropy]

300gph is nothing flow wise. You could probably run that through a 1/2 inch bulkhead. I would go with at least a 1 inch bulkhead in case you want to upgrade the flow later. 1 inch will let you safely flow 600gph. Are you going to supplement the flow with a closed loop or power heads? 300gph seems really low for a 50g by itself.

 

[EchoFish]

Oh, definitely I'll be doing some powerheads to supplement the flow.

Thanks for your advice. I'll probably go ahead and have them drilled at 1" in case I want to up the flow later.

 

[wave_happy]

I am a little concerned when you say that the sump will be "down the hall". Long horizontal runs must be well planned to avoid water backing up because of trapped air.

Exactly how far away will the sump be from the tank?
What are the vertical and horizontal distances?
Will the route of the plumbing require elbows or turns?

 

[EchoFish]

It won't be that long of a distance. 8-10 feet, 12 at the absolute furthest horizontally. Vertically will be a pretty short decline (from tank to sump). Regular height of tank (bulkheads near the top), run through the wall/closet behind the tank, to the sump on the other side.

Don't know if the sump will be on a stand or not. If it is, it will
be a low stand so as to increase the downward degree.

Turns or elbows? Probably. There will either need to be two elbows, or a slight turn if I can use flexible tubing. <---is that feasible?

Now I'm worried. I hadn't even considered this being a problem, since people commonly plumb their sumps to basements and the like.

 

[wave_happy]

I am not trying to scare you! Just want you to be aware of what to consider. You did say that you have never done anything like this before.

Now, since this is a very volatile subject, let me spread out a little kindling, pour on some gasoline and see what happens . . .

Plumbing to the basement is not too much of an issue. Runs that are primarily vertical have a tendency to flow without allowing pockets of air to accumulate.

In plumbing runs that are mostly horizontal however, air can get trapped. Trapped air can slow down the draining process and cause marital discord (tank overflows). Generally, there are two approaches to addressing this problem.

One is to use a relatively small diameter hose so that a continues siphon is created. The idea here is that the siphon will keep the water and air moving fast enough or by regulating the amount of air allowed in the plumbing, that there is no possibility of an "air-dam" forming.


NOTE: If the plumbing diameter is too small, then even with a full siphon running and no air being allowed in the plumbing there will not be enough flow to drain the tank as quickly as the pump can fill it.

The other method is to use relatively wide diameter plumbing to prevent any possibility of allowing a siphon to develop. This method keeps enough air in the plumbing that the water is "free falling". The diameter of the plumbing is so large that air dams cannot form.

Please do not ask me what size plumbing to use for X amount of water flow over Y Horizontal distance, moving Z Vertical drop, with A number of turns in the plumbing.


After that, there are other issues that have to be considered, such as noise, volume of water in the plumbing may be too much for the sump in case of a power outage or other failure of the pump . . .

 

[EchoFish]

Don't worry, I'm not upset that you brought this to my attention. Rather, I'm glad as now I can hopefully skirt another issue. Do you think it would help if I used flexible tubing for most of the plumbing, and got the translucent kind (food grade) so I can see any air accumulating?

 

[wonk]

I second the note for being careful, particularly since you don't have experience with this sort of thing. Plumbing to a sump can be deceptively difficult and somewhat dangerous to your floor and livestock. It's certainly a case of murphy's law in action. Having 12' of horizontal run seems really iffy to me. I have 2 feet of horizontal now and hate, hate, hate it. I hate all my plumbing for that matter. That's why I'm doing it all over again by setting up at 120 the right way (to my basement so I don't have any issue with space, etc).

Read, read, read! Don't take my warning as discouragement, but please!!! for everyone's sake (not the least of all your fish) get as much info on sump plumbing as you can b4 doing anything. I thought I knew enough when I did my 75g....Wrong!!

Doing the plumbing wrong will make your tank really unplesent to have and work on, but, don't fear...you can certainly do it right the first time, & you are are the right place to get the answers you need.

 

[EchoFish]

I read this Plumbing FAQ and it helped me understand a lot.

As for the sump placement -- I don't really have much choice. It's either a sump down the hall...or no sump at all. I have no basement, and the stand is so small I couldn't fit anything bigger than a 10 gallon through the door.

The length won't be exactly horizontal. It will be angled downward from the tank to the sump the entire distance. Not a very steep angle, but never completely horizontal. Does that have any effect?

I'm sure I'll have many more questions. Thanks to all your help, maybe I'll have a chance!



edited to fix the hyperlink

 

[wave_happy]

EchoFish,

That is a great link to basic plumbing. I would suggest though, that it does not begin to address the possible issues that you may encounter with a long horizontal run from the tank to the sump.

Anyway, your question was what sized bulkhead to get. The simple answer is the larger the better. It is easier to reduce the size of the plumbing if needed. It is much harder to increase the size of the hole.

You may not have any problems at all with the long horizontal run. If you can, set up a "dry" run where a small flood will not be a problem. You can make adjustments if needed and then move everything to the final location. If you have any any other question, let's know. Otherwise, let us know how it works out.

 

[EchoFish]

Thank you much for your help. I will certainly do a trial run first.
And where the sump will (hopefully) be located, it won't be a problem if there's a slight overflow. It used to be the washer/dryer closet so it's made to withstand a little water leakage.

Anyway, thanks again and I'll repost when it's set up.

 

[wave_happy]

You are very fortunate to have the availability of a utility closet.!! My main concern is that the tank will overflow if the plumbing to the sump does not drain correctly.