Hose diameters and glassware

Translated from German with AI assistance and reviewed by our editors.

Those who'd like to upgrade their external filter with lily pipes made of glass or stainless steel can choose from a vast range of such products in our shop. To make sure that the filter hoses match the respective external filter, please pay attention to choose the right hose size.

Hose diameters

Basically the various manufacturers offer filters with connections for three different hose diameters: 9/12 mm, 12/16 mm and 16/22 mm. The number before the "/" gives the internal diameter of the hose, the number behind it the respective external diameter. These different sizes are needed since the external filters and their performance are suitable for different aquarium sizes. For example: size 9/12 mm fits the Oase FiltoSmart 60, which has been designed for nano aquariums. Filters with a 12/16 mm connection, like the JBL Cristal Profi e701, for example, are commonly used for medium-sized tanks. Filters for bigger tanks as for example the BioMaster line by Oase come with a 16/22 mm hose diameter.

Lily pipe sizes

Filter pipes made of glass or stainless steel are usually sold in three different sizes: 10 mm, 13 mm and 17 mm. This number gives you the external diameter of the lily pipe. Since the filter hose needs to go over the tube of a glass or stainless steel pipe, the external diameter of the lily pipe must match the internal diameter of the hose. For example: a 9/12 mm hose has an internal diameter of 9 mm and fits a 10 mm lily pipe - the diameters are off one millimeter, as you can see, but this happens on purpose. All lily pipes, no matter their size, are always a little bigger than the matching internal hose diameter. This makes the first installation a little harder but ensures a tight fit so the hose doesn’t leak or slip off.

Overview

All in all, the following tubes are suitable for the respective tube sizes:

• 10 mm filter tubes: 9/12 mm hose
• 13 mm filter tubes: 12/16 mm hose
• 17 mm filter tubes: 16/22 mm hose

Exception: since we also offer glassware in 9 mm (not to be confused with 10 mm), a matching 8/11 mm hose is available, too. This hose is quite stretchy and it fits 10 mm tubes, as well.

Installation

As we've already mentioned above, the initial assembly can be a little difficult since the tubes are a bit oversized. In the following we'll give you some hints and tips to make this process easier.

Moisten both the end of the hose and that of the pipe, for example by dunking it in water. This way, the hose will slip over the tube more easily.

If you encounter greater problems with stubborn hoses, especially then they are of the more rigid type, heating the end of the hose can help enormously. Dip the hose end in very hot water for a little while. After some time, the hose softens considerably thanks to the heat. Now you can slip it over the moistened pipe quite easily. When the material cools off again it will contract and sit tightly on the lily pipe. For easy disassembly of the hose connection (e. g. for cleaning purposes), you can also fall back on this method. In that case, put the entire connection of tube and hose in some hot water.

The filter hose should be slipped over the tube and overlap roundabout 1.5 to 2 cm. A smaller overlap will increase the risk of leakage (for example in very curvy connections). A significantly longer overlap is unnecessary and would just make maintenance harder because it’s more of a hassle to take apart. For this reason, the hose should never be pulled over the pipe as far it can possibly go (up to e.g. a glass nub for attaching a suction cup).
To remove the hose from the glassware, push the end of the hose a little further up the lily pipe after moistening it. As a result, some moisture will leak into the gap. Now the hose can be removed from the filter inlet or outlet much more easily.

Tips on how to properly clean glassware can be found in this article.