The EHEIM Trough-flow-indicator is simply installed on the over-flow tube of the InstallationsSET 2. Now you can see when the filter output diminishes and so the filter must be cleaned. Do you have questions about this article ?
Reviews for EHEIM Through-flow indicator for InstallationsSET 2: Write a review
Mikko U. at 31.03.2016: Works great and looks pro.