Before I got this, I had a Hailea HL-BT1000... It was very noisy and its suction cups were terrible... Every morning when I woke up, I found it standing only by its cable... It really is night and day... Of course, Eheim Aquaball... And in terms of noise, stability, and biology

the worst filter does nothing waste of money don't buy it for anything....I had it in a 120-liter aquarium it did nothing and I cleaned it almost every day

Strong filter for aquarium 80X35X40cm 110lt.
The problem for me is that it has an intake from below, as a result, when you unplug it from the power, whatever has stuck on top of it, on the external side of the intake basket, returns to the aquarium water. This phenomenon could be avoided if the bottom part of the filter was inside, let's say, a "cup". For the same reason (water intake from below) it does not collect additional debris.
It has 5 positions for filter materials, which is sufficient.
It is quiet

Very good flow organic material! But when the cable is submerged in water, it leaks electricity and occasionally pinches my finger like static electricity. When I lifted it so that the cable does not touch inside, the pinching stopped. I have had it for only 2 months

Eheim always offers quality products, a reliable choice for a small filter (for a similarly small aquarium). 4 out of 5 stars, because like many companies, Eheim exaggerates how many liters its product can cover. 250 liters definitely does not cover it.

I use it in a 200lt aquarium and it is really excellent. It has 2 compartments with sponge and 3 compartments with biological material and it does its job as it should. The only negative thing someone can find is that it has a large size and it is visible inside the aquarium, but unfortunately we can't have it all. Recommended!