Marineland Penguin 350 Review

at 10:06 am

The Penguin 350 is perhaps the best value of any filter on the market. For a very low cost, you get a very reliable and effective filter that surpasses almost all other HOB filters, excluding its big brother, the Emperor 400, in biofiltration.


The inherent dynamics of HOB filters limits their biofiltration capacity. Biowheels eliminate this limitation.


  • A dependable filter


  • Use of Biowheels ensures adequate biofiltration


  • Use of biowheels allows full use of the flow rate for biofiltration


  • Very low cost, perhaps the best “bang for the buck” of any aquarium filter.


  • Easy maintenance


  • Cannot be considered “silent”. If absolute silence is at the top of your list, spend more money


  • Replacement cartridges can be an added expense, look under “Other information” for recommendations


  • Looses prime relatively easy during water changes (when the water drops to a certain level) and may not self prime on power up after a water change (may have to pour water into the filter to get it restarted).

Other information:

  • I don’t use the manufacturer cartridges. Instead, I use Bio3 Penguin Filter Cartridges, only using the clamshell and blue sponge, setting the carbon pads aside, and using blue bonded padding cut to fit, using four of these cartridges in each Penguin 350.


  • I have several “cut to fit pads”. Each week, I pull the cartridges, removing the blue bonded padding, replacing it with a recyled pad, and squeeze the blue sponge out into a bucket of water. The dirty pads are taken to the sink, rinsed clean with a dish sprayer, and then boiled for several minutes. Boiling returns the pad to “like new” condition (including fluffing it back up). This cleaned pad is then dried and stored for reuse. Using this process, I have not purchased additional media in several years.


  • The biowheels almost never need to be replaced. I have the same biowheels on a couple of Penguins that have been in use for over 20 years. The only maintenance I perform on biowheels is a weekly to monthly shake-out in a bucket of tank water. The exception to this would be if you have hard water, in which case calcium build up on the wheels will eventually force replacement.


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