The most common PVC pipe sizes for aquarium use are:
- 1 1/4″
- 1 1/2″
The size indicates the inside diameter of the pipe.
The smaller sizes (1/2″ – 3/4″ – 1″) are more often used for water returning to the aquarium via a water pump. The larger sizes (1″ – 1 1/4″ – 1 1/2″ – 2″) are usually used for gravity fed drains coming from the aquarium to a filter sump.
PVC pipe comes in different wall thicknesses with Schedule 40 being the most common and durable. Lengths of pipe can come in various lengths up to 20 ft long.
PVC connectors or “fittings” are available for each size with some that are able to connect different sizes. Fittings can be glued or threaded together depending on their design.