Plumbing a reef tank is something that might sound harder than it is. Even if you’ve never done much DIY work before, you can do this. Here is what to know about how to measure, cut and glue your plumbing and get it right the first time.
Choice of Piping
The most common choice for plumbing is PVC – a time tested material that is both cheap and easy to find at hardware stores in various sizes.
Rather than using rigid tubing, many people nowadays go with Flexible tubing. Varieties include Flexible PVC, Braided Vinyl or Silicone tubing. Bendable tubing allows you to gradually curve the pipe, rather than use elbow type fittings, which simplifies the setup and cuts down on cost. Softer tubing also will transfer less vibration between the pump and the rest of the equipment resulting in less noise.
Using Braided Vinyl or Silicone tubing does have a slight drawback however, in that you have to rely on barbed fittings and collars. Glued fittings are a better alternative. If the pressure in the line gets to be too much, there is more chance of "blowing a fitting" which can potentially cause a flood. This is more about taking a pragmatic approach to reduce risk when given 2 options.
A good choice is to use Flex PVC, commonly used for hot tubs and sometimes called Spa-flex. This glues up with the same solvent as regular PVC. While not as easy to bend as some other types of flex tubing, it can be softened slightly with a heat gun then bent as needed. Never try to paint Flex PVC.
Where to use Rigid vs. Flexible?
For overflow standpipes and certain other places, you may want rigid tubing. Other than that, flexible tubing can be used throughout.
Schedule 40 vs. 80
Most people use Schedule 40 pipe and fittings, generally white in color, for reef tank use. The difference with schedule 80 is that it has a higher pressure rating. Reef tanks have low pressure compared to a lot of other applications, so there is no advantage to using Schedule 80 on most fittings. Valves that are Sch. 80 are usually of a higher quality and might be worth the extra price. Many people simply prefer the dark gray color of the Sch. 80 fittings.
Both a miter saw and skill saw can easily make cuts to PVC and will result in a nice 90° cut that is harder to get with a handheld hacksaw.
Use a chisel or other sharp tool to bore out the inside edge of each section of hard PVC. This will make the system run quieter because water is less likely to roll inside the plumbing and create noise.
PVC primer and Glue is easy to use, and should be worked with in a well-ventilated area. Take care to not drip the glue on anything. There are many videos on YouTube on how to do it.
What type of Bulkheads should I use?
Link to product page on Bulk Reef Supply: Bulkhead ABS Thread x Slip (Thread on the Flange/Head side)
These are a good choice for the Herbie System. A removable, threaded fitting can be installed in the tank, and the outside end glues to a piece of PVC.
Bulkheads come ready to install and don’t require any extra glue, etc. but some people add a lubricant to the rubber gasket. This generally isn’t needed. The only type suitable is a silicone based type – Never use any kind of petroleum based oil on the gasket.
How to Install: The gasket should be placed between the flange and the glass on the inside of the tank. You generally want to tighten the nut to the point of contact, then go 3/4 of a turn past that point using a wrench if possible. Do not over-tighten, because the glass will crack. Once tight, it may be possible to spin the bulkhead in the hole by forcing it, even though the seal is intact.
Be careful with the tank once bulkheads are installed because of the lateral forces they can place on the glass if pressure is applied. Never allow the tank to rest with any part of its weight on a bulkhead.
Gluing pipe to Bulkheads
Most (if not all) bulkheads you will find are made from black ABS, not PVC. It is generally not advisable to join ABS to PVC using regular PVC solvent, but I have done so many times. Never had a problem. There is a special solvent for PVC to ABS connections that you can find if you are concerned.