Tetra - Whisper Power Filters
I have a Whisper Economy in my 30 liter planted tank, and I can say that the name is quite appropriate for this product. Besides being one of the cheapest power filters in the market, this is a pleasantly quiet, simple and efficient little filter. It hasn't given me any problems in the year or so I've had it. The Economy model, in particular, comes in simple black plastic and doesn't have a plastic cover but, of course, that's one of the reasons why it's cheaper :-)
I have a different opinion concerning Whisper filters. Of course they are cheap, but that alone should not be a selling point. The biggest drawback that I can attest to, is the problematic motor I had the Whisper rated for a 20 to 40 gallon tank on a 30 gal. long. The filter cloggs too easily and the water flows over the flow tube thus no filtrated water. But the biggest problem of all is the motor itself. If you have a power failure, once power is restored the pump (2 out of 3 times) the motor will not start on its own. You have to shake the flow tube to get it going again. I'll stick with my AquaClears.
This filter is very quiet I can say, I sleep with one in my bedroom :). But it doesn't do that good of a job I think. If you have a planted aquarium you can get the oxygen needs, but this filter is wimpy! I have a pretty full tank and it does not give sufficient water flow! Thus, I do not recommend it for aquariums with active fish.
This is the best power filter I have ever purchased! I have had three of these and NO problems have accord. Plus it doesn't make any noise for $12 to $50! It makes other brands look like air plane food! (It tastes nasty, costs more than the flight itself and makes you toot the whole trip!)
I have owned several of these over the years. Overall, I think they are only average at best. They are very reliable, silent and affordable but the constant changing of the pads that clogs up too easily, starts to become an expensive proposition. So I guess they are good for only sparsely populated tanks. This is definitely not a good Goldfish filter! I have switched to the Aquaclears and I recommend everyone else do the same.
I have been quite pleased with my Whisper 2 and Whisper 3 Filters. I do believe that they are a little overrated as far as what size tank each should handle (Whisper 2 is supposed to be for a 20-40 gal tank, really more like 20 or less). I have fixed part of that error in mine by using Diamond Blend activated carbon/zyolite mixture in the bio-bags in place of or in addition to the provide carbon. I have found that water flow is still fully adequate and the performance of the filter has been significantly increased. The mixture I refer to is a Marineland product, they also have carbon or zyolite only products.