# Bulkhead, slip or threaded?



## Okapi (Oct 12, 2007)

I am working on a 75 gallon paludarium and have decided to drill it and install bulkheads. I have researched bulkheads and drilling glass but I wanted to run a more specific question by more experienced people before placing my order for the bulkheads, fittings, and strainers. 

The bulkheads, as well as their fittings and strainers, that I am looking at come in slip/slip, threaded inside/slip outside, and threaded inside/threaded outside. First I was just going to go with slip/slip but I do not want to have to destroy the bulkheads if I glue the plumbing together and decide to change the plumbing later. So I looked into the threaded options, thinking that I can just use plumbers tape for the threaded fittings outside of the tank going to and from the sump. Would that be the smartest option? I originally don't expect there to be enough water pressure to require gluing the outside fittings but the possibility of a minor leak eventually starting there scares me. 

The bottom glass is tempered so the holes would have to be drilled low on the back glass of the aquarium. The plan is to use three of the same sized bulkheads, one connected to the pump to return water and two for draining water to the sump. The outside of all three bulkheads will be connected to 90 degree barbed fittings for attaching vinyl tubing that runs down to the sump. The return fitting will be angled straight down as it is receiving water from the pump, so it would be best to have a straight tube with no extra turns. While the two 90 degree drain fittings would be able to be angled slightly up if need be so that the highest point of the vinyl drain tubing will dictate the water level, allowing me to tinker with the level of the water inside the paludarium. I keep going back and forth on where I would like to have the water level so I would like to have the freedom to control the height using the drain tubing rather than the bulkhead holes. If angling the 90 degree fittings up is not advisable, I could loop the drain tubing up the back of the outside of the aquarium to the final height of the water level which would accomplish the same thing. The reason that I am using two drains that are the same size as the return, rather than one drain that is larger than the return is so that the substrate isn't flooded if one drain gets partially or completely clogged. Obviously I will keep an eye on them but you never know when a piece of a leaf or other debris will end up in the water or when a plant decides to go crazy with its roots.

So in summary, the question would be which would you use and why, threaded or slip?
Any other advice, experience or ideas would be welcome as well. I only get one shot at this and would rather have it be a success than a costly learning experience 
Thank you!


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## varanoid (Jan 21, 2011)

I prefer to use threaded along with Teflon tape as it give me the opportunity to redo anything in the future. I've never had an issue with leaking, even under the pretty powerful pressure from the return pump on my reef tank. And I have redone my plumbing schematic several times to incorporate more equipment and features so the threaded was more flexible in that way. Not that it couldn't have been redone with threaded fittings, it just allowed me to reuse and repurpose a lot of fittings and parts.


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## Kalle (May 14, 2010)

When you say that they have to be drilled low on the back glass, how low are you talking about? Just be aware of that drilling holes close to the edge can be risky and prone to cracking. Not sure if I remember it correctly but I think you shouldn't go closer than 1-2 diameters of the hole you're drilling. I would try and look it up just to be sure. There are different recommendations depending on the material you're drilling. 

If you after tinkering with different water levels decide on one, putting in a simple small internal overflow box can also be an option. The top of that will decide the water level inside the paludarium and not the height of the drain. It would also provide an extra protection from debris plugging your drains. 

I don't know what flow you're going to have and the size of the drains but going with two drains can also help keeping them from gurgling and being noisy. If the drain hoses exits below the water line in the sump it'll be pretty much completely silent.


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## Socratic Monologue (Apr 7, 2018)

Be aware that taping/doping plastic threads is advised against by manufacturers. It makes it much easier to overtighten the fitting and split it. Yes, many/most people use tape or pipe dope. I do sometimes, too. Sometimes I use plumber's lubricant, too. Sometimes I split fittings. I'm kind of a lummox when I'm doing this sort of thing, though.

I usually use threaded bulkheads and fittings (lots of aquarium and swimming pool experience, but I don't put drains on my frog vivs). This is mostly for ease of installation. Threaded fittings can be tightened during installation, but when I blow my first try on slip fittings, it is a lot of work to redo it. 

In reef tanks, I don't tend to reuse bulkheads; the washers need to be replaced anyway, and it is false economy, I think, to try to clean up a ~$10 bulkhead well enough that it seals, when even a slow leak could cost big$ in water damage. They likely won't get funked up too badly in a viv, though, so this worry might be misplaced here. Also, if you use slip fittings, you can cut out the bulkhead assembly and reuse it with a simple PVC coupling (less than a dollar), if you wanted to reuse the bulkhead.

Edit: Oh, this is for a paludarium, not a viv drain. I skimmed too quickly the first time through.


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## Socratic Monologue (Apr 7, 2018)

If you are worried about clogs that cause the water level to rise, you could install a float switch at the maximum water level and use it to shut off the return pump. Will there be a sump? If you use a canister filter, then there's no worry of overfill from a clog (though a clogged canister can itself get damaged).


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## JimM (Oct 2, 2018)

Slip always - just habit, but also I'm then not worried about threads, over-tightening etc.

BTW, I'm a fan of soft-plumbing things wherever possible.


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## varanoid (Jan 21, 2011)

Socratic Monologue said:


> If you are worried about clogs that cause the water level to rise, you could install a float switch at the maximum water level and use it to shut off the return pump. Will there be a sump? If you use a canister filter, then there's no worry of overfill from a clog (though a clogged canister can itself get damaged).


It never hurts to have protections in place for disasters especially when water is involved. Redundancy is also prudent. I had sensors on the floor of my cabinet that housed my sump which would cut power to the return pump if they were ever tripped by a flood. This was in addition to a float switch. Probably overkill for a smaller volume of water that one would expect in a vivarium, but maybe not if water was a major feature. Something to consider.


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## Dr. Manhattan (Oct 28, 2016)

I've used both, no leaks with either. I like to use that pink heavy duty Teflon tape they sell at HD/Lo's. I guess with threaded there's more flexibility. I prefer to use hose barbed ended fittings also. That's what I used on this paludarium for my stripe necked musks. I was doing a sump with a trickle tower and algae scrubber (yah I'm willing to try and adapt some of the techniques our reefer friends are using) but just ended hooking up a Cascade 1500 canister to it. I just want all my stuff to be plug and play so I can enjoy it and not have to tinker.


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## jgragg (Nov 23, 2009)

Threaded, with teflon tape, on the exterior side. Hand tight, no wrenching. Moderately firm - far from heroic - hand tightening.

Slip on the internal, strainer side. No glue.

I like my drains to be fatter than my returns. My standard is a 1/2" return from pump, but a 3/4" drain to sump. Cheap flood insurance. Real cheap, but quite good.

My fave glass holesaw vendor includes instructions. https://www.glass-holes.com/

They tell me not to approach an edge closer than 1 diameter of the hole I mean to put in. Thus a 2" hole runs from 2 to 4" distance from the nearest pane edge.

Just drill your drain as low as you can (determined by diameter of the hole-to-be, as noted above). Then, establish your dead pool elevation with a standpipe between the bulkhead and strainer. A little piece of schedule 40 PVC pipe serves well on a 3/4" bulkhead / strainer rig. This way, it's super easy to modify water level - just cut off a little of that standpipe, or slap in a longer piece. *No screw, no glue, just push it in and pull it out.* And, you'll never kick yourself for drilling your hole too high - it's as low as you ever could have made it.

If you wanna get fancy you can put a few smaller holes or slits at the bottom of the standpipe, to not just drain from the surface but also draw from near the bottom. This is more important in deeper-water setups, or with messy eaters like turtles.

Hopefully this is all clear. Other have success doing other stuff, but all this is what works best for me. I have screwed up most everything at least once. What I've given here is the emergent wisdom of a whole lot of messing around.

Good luck!


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## varanoid (Jan 21, 2011)

Socratic Monologue said:


> Be aware that taping/doping plastic threads is advised against by manufacturers. It makes it much easier to overtighten the fitting and split it. Yes, many/most people use tape or pipe dope. I do sometimes, too. Sometimes I use plumber's lubricant, too. Sometimes I split fittings. I'm kind of a lummox when I'm doing this sort of thing, though.
> 
> I usually use threaded bulkheads and fittings (lots of aquarium and swimming pool experience, but I don't put drains on my frog vivs). This is mostly for ease of installation. Threaded fittings can be tightened during installation, but when I blow my first try on slip fittings, it is a lot of work to redo it.
> 
> ...


I've never considered using pipe dope before for any of the animal applications that have arisen. Have you used pipe dope in an animal application? I've never used it because Teflon has worked just fine in every application I've used. Hand tighten in most applications. No need to crank on it. Cranking on it will damage the threads and thus the integrity of the joint/union of two pieces.


Also on a completely unrelated dart frog note, I reuse bulkheads a lot. Sometimes the gasket needs to be replaced, but that is it.


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## Socratic Monologue (Apr 7, 2018)

varanoid said:


> I've never considered using pipe dope before for any of the animal applications that have arisen. Have you used pipe dope in an animal application? I've never used it because Teflon has worked just fine in every application I've used. Hand tighten in most applications. No need to crank on it. Cranking on it will damage the threads and thus the integrity of the joint/union of two pieces.
> 
> 
> Also on a completely unrelated dart frog note, I reuse bulkheads a lot. Sometimes the gasket needs to be replaced, but that is it.


I have not personally used pipe dope. Teflon tape is what most people use, I think, but it can/does make it much easier to split fittings (it bulks up the diameter of the female fitting more than the male fitting is sized to handle). I mentioned it because Okapi strongly implied that this is a new skill set in the learning phase; splitting PVC fittings is something that happens most to the inexperienced. And, I gave this advice as someone who is himself kind of a bull in a china shop sometimes, so people who don't see themselves that way might not find the 'no tape' advice useful. None of this has to be 'up to code', so whatever works is best.

I agree that bulkheads in a typical frog drainage application probably are worth reusing with a new gasket. Reef tanks get a lot of crusty precipitate on everything, so I woudn't ever reuse them in saltwater applications. I'm not sure how a paludarium would gum up a fitting -- not too badly, perhaps.


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## davecalk (Dec 17, 2008)

Jgrag had a great post with lots of wisdom behind it. Using a stand pipe with slits in the bottom with the stand pipe not being glued in is a great tip. 



varanoid said:


> I've never considered using pipe dope before for any of the animal applications that have arisen. Have you used pipe dope in an animal application? I've never used it because Teflon has worked just fine in every application I've used. Hand tighten in most applications. No need to crank on it. Cranking on it will damage the threads and thus the integrity of the joint/union of two pieces.
> 
> 
> Also on a completely unrelated dart frog note, I reuse bulkheads a lot. Sometimes the gasket needs to be replaced, but that is it.



As far as pipe dope, think about this. It is used on all potable, drinking water. In the trades, I tend to use both teflon tape, 3 wraps total, and then just a bit of pipe dope. The combo prevents all leaks. But with our tanks not being pressurized like city water is it probably is not an issue. As far as reusing bulk heads, go for it. Replacing the gasket is cheap and easy. You could also just use silicone to replace the gasket.


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## Socratic Monologue (Apr 7, 2018)

davecalk said:


> As far as pipe dope, think about this. It is used on all potable, drinking water.


Well, so is chlorine. The legal limits in the US on copper and nitrate content in drinking water are higher than most people would willingly subject their frogs to, as well. 

It isn't that I'd claim that pipe dope shouldn't be used on animal applications; I actually have no idea on that. I'm just pointing out that the fact that we tolerate it in drinking water in no way implies that it is safe for frogs. Neither does it imply that it _is_ safe; there is simply no reliable connection.


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## davecalk (Dec 17, 2008)

Socratic Monologue said:


> Well, so is chlorine. The legal limits in the US on copper and nitrate content in drinking water are higher than most people would willingly subject their frogs to, as well.
> 
> It isn't that I'd claim that pipe dope shouldn't be used on animal applications; I actually have no idea on that. I'm just pointing out that the fact that we tolerate it in drinking water in no way implies that it is safe for frogs. Neither does it imply that it _is_ safe; there is simply no reliable connection.



Don't think I should bite on that one but.... 

They serve two different purposes. Chlorine is there to kill bad things in the water that if left there would kill or harm many more people than if it were left out. 

Some home owners are concerned with teflon tape too. I know of plumbers who had to remove teflon tape and use pipe dope because of uniformed home owners worrying about nothing.

Pipe dope has been used in plumbing for ages. 

FYI: There are far more toxic things found in decomposing waste materials / wood / etc. then you need to be concerned with in pipe dope. 

BTY if you are misting / fogging your tanks you are flushing those out too. You probably have a lot better things to worry about then this.

Lead solder in old plumbing would be far more concerning.... But that too gets flushed out if the faucet is run.

Lets not hijack the threat with needless concerns.


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## Socratic Monologue (Apr 7, 2018)

davecalk said:


> Lets not hijack the threat with needless concerns.


I'm sorry -- I originally read the concern about pipe dope as a contamination concern. Now that I reread it, I think I read into it more than was originally intended. I didn't intend to add crazy irrelevant talk; I actually thought that was the issue at hand, and took your comment about use on potable water systems in that context.

I come from the aquarium hobby, where the (fallacious) argument "if it is safe for people to consume, it is therefore safe to use in an aquarium" is quite common, and so I'm overly sensitized to it.

My mistake.


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## davecalk (Dec 17, 2008)

Socratic Monologue said:


> I'm sorry -- I originally read the concern about pipe dope as a contamination concern. Now that I reread it, I think I read into it more than was originally intended. I didn't intend to add crazy irrelevant talk; I actually thought that was the issue at hand, and took your comment about use on potable water systems in that context.
> 
> I come from the aquarium hobby, where the (fallacious) argument "if it is safe for people to consume, it is therefore safe to use in an aquarium" is quite common, and so I'm overly sensitized to it.
> 
> My mistake.


No problem. I as well apologize if I came off a bit abrupt. I do understand how water quality affects the aquarium industry. Chemicals, chlorine, chloramines, pH, nitrates, nitrites, etc. all affect water quality so much more in the aquatic community of the aquarium.

Chemicals also affect our beautiful glass communities, but not nearly as much as they do in the aquarium industry. We have so many more things in our favor. We have soil, and plants, and clean up critters, and we regularly flush out these systems with regular sprayings, and our frogs are not exposed as much to the bad things as are the fish who have to live in the water all the time. We all love our beautiful frogs and the wonderful tank that house them. 

Have a wonderful Thanksgiving weekend.


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