Aquarium Plumbing Guide Part II: Basic & Advanced Plumbing Schemes

Marcin SmokBy Marcin Smok 5 years ago
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In this second part of the article I would like to present two example plumbing schemes for the beginner reefer-plumber. Both those ideas are based on my own as well as other hobbyists setups and require little to no previous plumbing experience. They can be expanded and modified to individual hobbyist’s needs. Once you learn how to build a basic PVC grid, other, more sophisticated systems would be much easier to plan-out.

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 In case you missed the first part, here it is:

 Before I step into explaining each of the two plumbing ideas, I would like to mention one particular part of the grid- overflow drain section. If not planned correctly, it tends to create a lot of noise and be inefficient for the flow needs through sump. The most simple way to drain water from display aquarium to the sump is to install a vertical piece of pipe coming from bulkhead to the top of overflow. Sure it’ll work to a degree, but the noise of water gurgling inside the pipe is so annoying it can ruin the “calming effect” of a home reef environment. The noise comes from air trapped in pipes and as with any plumbing project, a fish tank drain needs a vent to release that air. There are many ways to overcome this problem, but the so-called Durso drain is a proven design that works on almost every aquarium you incorporate it in.

Durso drain is a “h” shaped piece of plumbing with an airline tubing sized hole on the top. What this device does is it drains water through the “c” section down the pipe while letting the air escape through the hole on top (see drawing). The whole purpose is to silence water going down the sump and prevent air-clogging (which present itself by a gurgling sound from the drain). Durso pipe is quite easy to made from readily available PVC fittings. Here’s a list of parts needed to put it together (size depends on your drain pipe diameter,obviously). See below picture for reference:


a) straight piece of PVC pipe running down the overflow

b)one “T” shaped fitting

c) two short pieces of pipe, extending from two ends of “T” fitting (or one if you buy an inside cap like in my case)

d) PVC cap

e)one 90° elbow

f) bulkhead coupling, to attach vertical piece of durso pipe to the bulkhead, check your overflow bulkhead size and connector to determine correct fitting

g)(optional) PVC strainer, can be purchased online, strainers can have SLIP or THREAD connectors, choose elbow piece accordingly

h) short piece of aquarium airline tubing

 To put durso pipe together, just follow the illustration above. I suggest not to use PVC cement in point where straight piece of pipe connects to the bulkhead adapter, in case durso pipe needs to be cleaned or in situations where you need to flush a fish who jumped into overflow section and cannot be removed any other way (just make sure it sits firmly in the connector coupling. Word of advice: make sure your sump can handle extra volume from the overflow before flushing it.

 1. Basic plumbing build with overflow containing both drain and return pipes

plumbing easy

 Below is my suggestion for most simple, fully functional plumbing grid build for a fish tank . It’s targeted for systems where no additional equipment (media reactors, external refugiums etc.) will be feed from return pipe. When you are certain you won’t expand your plumbing and you just want to create proper flow through the sump, this scheme is for you.

Let’s start with the drain section,from the point where bottom side of bulkhead connects to the drain pipe:

 a) first, determine the kind and size of bulkhead and fitting needed to connect it to PVC pipe

b) with a combination of 90° elbows or using flexible PVC pipe, create a section that’s going straight down to center of filter sock holder

c) the use of union type, swing valve in drain pipe does two important things:

– shut the water down allowing for removal of durso pipe without draining the overflow

– allow for quick removal of bottom section of drain to change filter sock (see point “d”)

d)this part consist of straight piece of pipe extending from union valve to the filter sock and a 90° or 45° elbow on the other end; the elbow lessen the splashing water sound and reduce air bubbles entering the system; when changing filter sock, simply unscrew bottom nut from union valve and remove filter sock with PVC pipe piece

 Return section in this example is equally simplistic and from return pump’s outlet it consist of:

 a) connector fitting from pump’s head to PVC piping; usually a male or female THREADxSLIP type; check with your pump’s specs

b) relief manifold with valve- when pump’s gph ratio is higher than your overflow capability to drain water, we need to reduce the flow; there is a misleading conception of installing a swing valve right after pump’s outlet and partially close it to lessen gph- not only it shorten return pump’s life by forcing it to operate at higher pressure and therefore radiating more heat into surrounding water, but it’s a simple waste of energy; the use of relief valve allows to reduce the flow by directing some of it back to the sump and, for example, creating more chaotic flow patterns in refugium section; in addition to that, we can always modify this branch to accommodate media reactor fed by return pump; relief valve manifold consist of “T” SLIPxSLIP fitting, a swing or gate valve ( if swing valve is used, buy THREAD type to swap it easily on a later time, if needed) and a series of PVC pipe pieces and elbows to direct the flow where you want to

c) this section extends from the “T” manifold to bottom part of display tank’s bulkhead and incorporate a swing valve; this valve is not used to reduce the flow, but to stop it completely after shutting down return pump- a overflow section of return line can be removed without draining the overflow

d) last part is the bulkhead-to-PVC pipe fitting, a straight piece of pipe and 90° elbow extending from the overflow box to the tank; I am a fan of using Loc-line return where you can direct the outlet to your liking, so I used a THREADxSLIP 90° elbow and male THREADx lock-line reduction fitting;

 That is a simple, working plumbing grid for your basic flow needs with a little bit of expandability included. However, if you plan to run more than just display tank-sump loop through your return pump, I anticipate you to try the advanced plumbing scenario.

 2. Plumbing build with two, return pump’s fed media reactors and dual outlets.

 plumbing advanced

My second scheme for a plumbing build is a fuse of basic, display tank-sump flow scenario expanded to accommodate media reactors and other equipment. The drain section of this build is identical to basic plumbing scenario explained above, please refer to it when putting your own drain piping. In situations where two or more overflows are present, simply copy the same scheme multiple times, directing the drain outlet to one or more filter socks.

The return half of this build consist of (beginning on the return pump’s outlet):

 a) relief valve manifold, which is explained in details in point “b” of the basic plumbing scenario; this branch can be further expanded and transformed to accommodate additional equipment, such as inline UV sterilizer, diatom filter, external refugium or others

b) media reactor manifold- (look at the picture below for reference )

reactors manifold

– the idea of feeding media reactors through return pump help saves energy and space of additional pumps in the sump; it consist of:

-a “T” coupling and 90° elbow (if needed) directing some of the flow to the reactors

-a gate valve for flow adjustment through media reactors; gate valve, despite being more expensive, allows for precise flow tweaking; as I mentioned before, make sure to close the valve and open it all the way once a month to prevent calcium buildup that can destroy the rubber seal inside the gate; also important is to choose THREAD type of valve so it can be reused in future projects

-a THREADx BARB reduction fitting to connect flexible tubing to reactor’s inlet, this part is where flexible tubing is more convenient- most commercially available reactors use barb connectors and tubing allows for easy maintenance; run the outlet tubing all the way to filter sock, attaching it to your PVC pipes with zip ties; filter sock will trap any particles that may escape from media reactor; always use quality, non-transparent tubing and secure ends to barb connector using nylon or stainless steel hose clamps

c)back tank detail

in my example, display tank has dual outlets,so the part right after media reactor manifolds split into two equal lines using “T” coupling, drawing above shows side view of display aquarium’s back wall- a 90° elbow (or two 45° elbows if you have enough space and prefer gentle slope) connects the “T” coupling with straight PVC pipe, which in turn connects to the bulkhead using another 90° elbow with adapter” it’s important to make those pipes as close to the tank as possible, that’s why I used readily available MPTx slip elbow; in-tank side of the outlet consist of MPTxLOC-LINE coupling with 6″ of loc-line and round or wide spout

bul;khead return


That way we planned-out an all-in-one plumbing scheme that is easy to put together and works flawlessly. Please read carefully both parts of Aquarium PVC Plumbing Guide and enjoy building your own closed systems. Don’t hesitate to contact me with any questions and comments you may have.

You can print and use the above drawings for reference, just right-click on image and click “Save picture As”

  DIY, Equipment
Marcin Smok

 Marcin Smok

  (168 articles)

Marcin Smok is a reefer, photographer, traveler, SCUBA diver and and avid DIY-er. He has been keeping freshwater fish tanks since he was 9 years old and saltwater tanks for the past 10 years. Check his photography site at and follow his Facebook profile

  • OceanDunk

    Marcin, thanks for a great article. As I in the early stages of planing for a 93 Cube, this was very helpful.

  • Marcin Smok

    I’m glad you like it, hope the second half help people with their plumbing ideas.

  • Dan Kelsch

    I am not a fan of the valve on the drain. If you would ever forget to open it after doing maintanence you would overflow the tank when the return pump is powered up. This might be remedied by adding an additional hole to the bottom of the tank and plumbing it with an open stand pipe to return water and prevent the flood.

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