I bought this because of good reviews and pre-filter in order to achieve a longer service interval in the external filter. Ordered the filter in the discus ornamental fish paradise. Fast Delivery. The filter is about as big as two small, stacked cans. The filter can be operated either with two or only with a filter cartridge. Just the small release button push and remove the lower filter element. The filter can also be easily opened for cleaning. Inside the filter there is a foam element, as I know it from normal internal filters. The installation and connection to my Terratec 700 external filter was quick and without any problems. Since the outlet of the external filter is a little too thin, the pre-filter is not held on the outlet pipe. I've been on the bottom of the discharge pipe just a few layers of adhesive tape wrapped until the tube tightly sucking fit easily into the filter. Good that the pipe was thinner. Conversely, I would not have known me so easy to help. Since I was interested in how much power the external filter loses through the prefilter, I had plugged when changing the water, as could be seen, as the water gushes out above, taken from the pre-filter again and again. I could not detect any change in the Auslasswasserstrahl. What I can not say looks at a pre-filter for longer in operation. After a few days of operation, the white filter material was dyed dark already. The next upcoming water changes I have cleaned the filter. It came to some "fish poop" and dead plant remains to the fore. As dark as the cleaning water was, the filter has been working well. A pleasant side effect is that no shrimp or baby fish can be sucked more. Shrimps hold even like in the pack under the filter bowl on. I can definitely recommend the filter and assume that the outer filter needs to be cleaned less often. Strong buy recommendation.
