HydorInternal Filter CRYSTAL 300 Aquariums Larger than 200 Litres, 2 Stages, Activated Carbon and Venturi Kit Included

Its an OK filter but I wouldn't really recommend it. On a plus side it has an internal container that could hold carbon or biomedia like Seachem's Matrix (a very small amount) and its easy enough to replace the included sponge with your own higher PPI foams or some filter floss for water polishing duties. In general though the way it fits together is poorly designed - specifically the way that the filter cylinder attaches to the pump motor.Its a pretty powerful pump and I question the wisdom of such a small filtration sponge combined with such a powerful pump. I bought it because its adjustable and I thought I could tweak it down a bit, but even on lowest setting it was still far too powerful for the 110 litre tank, I had it in, and yet would never provide enough filtration (in terms of sponge volume) for a larger volume tank. It was pretty useless at clearing cloudiness after a substrate change, despite being left on for several days before being removed for stocking with fish. Of course there are some fish species that LIKE that kind of current, but it would be the exception rather than the rule

Totally silent,so easy to clean and does a great job with Goldfish !!At first I could not fit the base to the pump section but I noticed the plastic grid holding the sponge had a lip at the topwhich slots into the filter media box, this was too long and preventing closure so I cut off about 3 mm. and now it is perfect.Doran L

Good filter for the size, quite, keeps the water clear, easy to clean.

I've had these filters for about 8 years water quality excellent would definitely recommend

the best