Featured is a LED filter cartridge change indicator light that flashes when the cartridge becomes clogged with debris, providing a reminder that it’s time to replace the cartridge. A great benefit of the Aqueon QuietFlow® filters is the internal pump design that helps dampen noise, eliminates leaks and is self-priming, meaning it starts up automatically after cleaning or power interruptions. Higher flow rates also ensure a higher dissolved oxygen content for healthier, more active fish. There are five total stages of filtration–mechanical, chemical, biological and an additional specialty pad–for the cleanest, clearest, healthiest water. Stage 1 – Dense floss removes particles and debris.