Closed Loop return through a bulkhead?

[TriniStylez]

I am just planning out my closed loop and want the return through a bulkhead in the bottom of my tank. I seem to remember someone telling me this was a bad idea but I forget why. I don't see how it is and Im pretty sure its done quite often but just wanted to make sure. Is there some kind of downside to having a closed loop return through a bulkhead in the bottom of the tank? I want to keep the closed loop outlets all underwater along the bottom of the tank. There will be about 6 of them. This is a 6 foot tank but very shallow at only 19". I am using a Sequence 1100 series pond pump (with saltwater seal) for the closed loop. I think not having the closed loop at the surface will be fine because I am going to get quite a lot of flow from my Mag24 return pump as well.

What do you think?

 

[Solitaryensis]

Do you plan on having 45's coming out of the bulkheads at the bottom? Ive seen this done before but i think you would have much better flow patterns coming from the top (and not to mention more control). But outside of this, i dont think there is much downside to doing it this way. If you think you will have enough flow from the mag24 as a return, why not skip the CL all together?

 

[TriniStylez]

You really think the return would be enough flow? Its actually going to be a bit restricted by elbows and distance. I REFUSE to have any powerheads at all in this tank! I figured that with these big pumps, I wouldnt have to worry about head loss, elbows or basically anything. I could just plumb it any way I want and never loose too much flow!

Im just not so sure a mag24 return would give enough flow or even enough random flow...

 

[lark]

I think after the weekend I just had, I can attest to the fact that the biggest downside is what happens if you have any leak or other problem.

I have a closed loop with a return through the bottom. I posted here about an issue I had with small leak in the pvc right under the bulkhead (but, unfortunately, just above a ball valve). I decided that a short-term fix was a bad idea, so I plugged the bulkhead (with great effort), and cut the pvc below the bulkhead. I fixed the leak. Somehow, though, in screwing the new plumbing into the bulkhead, I must have done something to make the bulkhead's gasket slip, and it start to leak at the bulkhead.

So that's your downside. Every drop of water needs to come out in a situation like that with a hole in the bottom of the tank. The next 15 minutes was filled with a stressful perpetual race -- draining the entire tank while keeping a bucket under the bulkhead and emptying it as it got closer to full.

I don't know that there's any other downside, but at that moment, I sure would have preferred a side-tank return.

 

[TriniStylez]

Yeah...I guess using as few bulkheads as possible is a upside to any tank. I already have the hole drilled though. Maybe I should just cap it leave it out for now. I have never just capped a bulkhead though. How safe is this? Im guessing its pretty safe though!

 

[lark]

Well, if you already have a hole there, I'm not sure that having plumbing there adds much of a burden or risk.

How to cap, if you decide to cap, probably depends on whether you plan on using the bulkhead in the future and whether it's slip or thread.

The safest way to cap a bulkhead, would be to use a slip bulkhead and use pvc primer and cement to put a smal length of pipe and a cap on either end. If you do that, though, you can't use that bulkhead in the future. It's just a cap. You'd have to drain the tank and take it out to use it.

If it's threaded, the way that would provide you the most options in the future is to buy threaded caps and screw them in, using teflon tape on the threads. That way, if you want to use the hole in the future, you'd just have to remove the caps. On the tank side, I might do this by getting a male adapter, and cementing a short lenght of pipe to it, and then cementing a cap onto the pipe. The advantage of doing this is that it will stick up out of your substrate a little, so it will be easy to find if you ever need to get to it, and you'll have a better grip on it to unscrew it.

If you have a slip bulkhead and want to preserve your options, you'll need to cement in a female adapter, I would think.

Note that you don't need to plug both sides of the bulkhead. You could get away with just doing one. I'd do them both though, for a couple of reasons. First, as my last post makes clear, a little redundancy seems worth it when you just spent the weekend almost putting 100 gallons of saltwater on your floor. Second, it will be easier later. If you decide you want to get to the underside later, you can just unscrew the plug on the bottom and work your plumbing without having to do anything up top, since it will already be plugged.

 

[TriniStylez]

Cool thanks. I guess since I have the hole and really do want to have the closed loop return through it, I may go ahead with it even though Im a bit scared after your story!

 

[lark]

I think the important thing to remember is that even thought it's on the "return" end, the water doesn't know that. It will drain out of that return just like it would out of an overflow. Accordingly, a ball valve or some other way to turn off the water is desirable on that side of your pump. Any plumbing leaks, problems, or other issues below the ball valve are easy to deal with -- you just shut off the water and fix 'em. It's the ones right at the bulkhead or just below it and before your ball valve (which was my situation) that are the problems.

I've read some stuff that says that adding a bead of silicone to your bulkhead can help make it more leak proof, but others who think this can mess with the integrity of the gasket.

 

[TriniStylez]

Well if there is a power outtage for example, the closed loop should be fine though right because its just that, a closed loop. There should be no water draining anywhere if the pump is turned off. Unless of course there is a problem...

How close to the bulkhead can you put a ball valve then?

 

[lark]

I have a small length of flexible pvc cemented right into a bulkhead, and then right into my ball valve. It's about 2 inches -- just enough room that if I ever needed to cut the pvc to take out the bulkhead, I could do it.

So that means there are really only three areas that could fail above the ball valve -- the bulkhead itself, the place where the flex pvc is cemented into the ball valve, or the place where the pvc is in the ball valve.

Right -- a closed loop is difficult to flood. Unless, of course, the volute on your pump cracks. Or your bulkhead gasket slips. Etc.

 

[liveforphysics]

I have 18x 1" bulkheads and 4x 2" bulkheads in the bottom of my reef. There is no greater chance of having a bulkhead on the bottom leak than one on the side.

Stick your bulkheads in a place that works with your plans for how you want your tank to be.

Also, your mag24 is definately not going to be adquate for flow alone. You most definately need that sequence helping out. The mag24 is also a big of a powerhog with pretty poor flow. You may want to considder other pumps like the sequence dart, or even the snapper. It may keep you from requireing a chiller.

Best Wishes
-Luke

 

[rstark33]

Just a note, use silicone grease, not silicone glue or caulk. You can get the grease at a dive shop, it is used on all o-rings in scuba gear to ensure a water tight fit. Put a little on the gasket of your bulkhead, work it in with your fingers and keep it very clean. the bulkhead will seal very well and can be removed in the future as well.

 

[TriniStylez]

<a href=showthread.php?s=&postid=10881370#post10881370 target=_blank>Originally posted</a> by liveforphysics
I have 18x 1" bulkheads and 4x 2" bulkheads in the bottom of my reef. There is no greater chance of having a bulkhead on the bottom leak than one on the side.

Stick your bulkheads in a place that works with your plans for how you want your tank to be.

Also, your mag24 is definately not going to be adquate for flow alone. You most definately need that sequence helping out. The mag24 is also a big of a powerhog with pretty poor flow. You may want to considder other pumps like the sequence dart, or even the snapper. It may keep you from requireing a chiller.

Best Wishes
-Luke

Yeah I figured that out after I got the Mag24

I guess I will have to use it for now but will most likely switch it when I can.

 

[BeanAnimal]

I would not use the grease on the gasket unless you are very careful. It makes the gasket very slick and cause it to deform under the pressure of the flange.

All of the plumbing should be supported solidly. It should NEVER hang on the bulkheads or put an lateral pressure on them. If you do it right, you should never have a problem

 

[billgraf]

I drilled my tank very low in the back for returns from closed loop, and have a manifold that will be under a deep sand bed, I hate powerheads too. I say go for it

 

[TriniStylez]

<a href=showthread.php?s=&postid=10883006#post10883006 target=_blank>Originally posted</a> by billgraf
I drilled my tank very low in the back for returns from closed loop, and have a manifold that will be under a deep sand bed, I hate powerheads too. I say go for it

How did you plumb the outlets for the closed loop? Just out from under the sand?

 

[billgraf]

I have 2 -1 inch bulkheads that are feed off from reeflo hammerhead.
each bulkhead feeds a 1.25 pvc manifold with 4- 3/4 locline. If I had to do it again I would have drilled bigger bulkheads for the returns.
I have 2 1.5" BH with strainers feeding the Hammerhead.
Just did my first test fill and flow is great!

 

[TriniStylez]

Did you raise the strainers a bit with PVC or are they right on the bulkheads?

 

[billgraf]

I have the strainers closer to the top, about 6" from top water level. It think it would have be better if they were lower for the added water pressure to flood pump, but I already had 2 holes really low and the more holes that are low in tank increase your chances of major leak.

 

[TriniStylez]

Oh ok. My closed loop is being fed through the bottom and I dont really want anything sticking up into the tank much at all. I really just want it up enough to not be sucking in sand. Its a very shallow sandbed anyways though.