Aquarium Plumbing: True Union Ball Valves and Why You Should Love Them

True union ball valves allow you to easily disassemble plumbing for cleaning and changes

True union ball valves allow you to easily disassemble plumbing for cleaning and changes

One of the cool things about the reef aquarium hobby is that you tend to pick up some useful skills by accident. If it wasn’t for the reef-keeping hobby, I may never have developed a love of photography and videography. On the more practical side of things, I learned more than my fair share about plumbing (and esoteric things like Rinnai tankless water heaters).

The plumbing mantra

I will let you in on a little secret about plumbing that is specific to reef aquariums. It’s my mantra, and I repeat it every time I do a new plumbing project. Plumbing is not about gluing pipes together and hoping for no leaks. It is about being able to take it apart later.

Reef aquarists are tinkerers by nature, and it is only a matter of time before we look at our systems and decide, for better or for worse, that things need to be changed. How often do we decide to install a new piece of equipment such as a skimmer or reactor and need to rework plumbing lines to account for them? How many times have we had to change plumbing to accommodate a new return pump?

If you imagine a reef tank as a little city, think of the plumbing as roads and subways. They are the first things built, and then the city grows up around them. One day you will need to get back in there to rework things and there will be a massive network of equipment and wires blocking the way. It is at that moment that you realize the true value of quick disconnects.

What is a true union ball valve?

That brings us back to the true union ball valve. A true union ball valve is essentially a ball valve flanked by a union on each end in a nice compact package.

Having said that, not all valves are made the same. Cepex makes the kind we use extensively. There are several brands of high-end plumbing, such as Hayward and Spears, but it appears that Cepex has a nice combination of quality and price point.

Can you find less expensive valves and unions at the local hardware store? Yes! Should you do that? No! Quality parts, especially valves, are amazing to work with. Super-cheap parts you find at a hardware store can be a total nightmare in comparison. It’s hard to get the sense of the difference just by watching a video, but believe me the feel is completely different.

Last thoughts on plumbing

In summary, there is a major drop-off in quality moving from a high-quality valve to a mass-market hardware store valve. Like most things in the hobby, it’s best to do things right the first time. And what better place to start than the plumbing?


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About Than Thein

Than Thein is the owner of Tidal Gardens and Advanced Reef Aquarium. Than's love for all things underwater began early on when dogs and cats were strictly off limits, but a fish tank? Sure! What started with a 10-gallon goldfish tank eventually turned into a 5,000-gallon greenhouse coral propagation system. In addition to coral aquaculture, Than's other hobbies include scuba diving and underwater photography and videography.


  1. Paul Baldassano says

    That ball valve pictured is definitely about the best valve you could buy. I use a lot of valves and fittings as I used to be a plumber many years ago but now I am an inventor. I do a lot with PVC especially for my sprinkler system, boat and reef tank as I am always adding or changing something just for experimentation. I want the best parts I can get but I also want to be able to afford them. I tend to use a ball valve (made in America) that has female threads in it. Then I add a shoulder nipple (small length of pipe) and to that I add a union. That is a much cheaper way to go and you can still take it apart. You open the union and screw off the ball valve. I have those things all over my house as I replaced all of the old valves with washers that were installed in the 50s. (stupid invention, you would think those old guys would have known better)
    Ball valves are the way to go for something you want to open all the way or close all the way. If you have anything you want to adjust, like a skimmer, then a gate valve would be the way to go.

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