Penguin 350

Written by Kmuda. Posted in HOB Filters




Eliminate toxic ammonia and nitrite on contact. Extra large BIO-Wheels provide superior biological filtration - 10 times more than other power filters. Adjustable intake system draws water from bottom AND mid-level for total water circulation and filtration. Innovative vented-hood reduces noise for quiet operation. Clear two-piece design means unobstructed view and convenient access to easy-change, longer-lasting, Rite-Size mechanical/chemical filter cartridges. Traps more debris and removes more odors, discoloration, and impurities. Models 200 and 350 feature an additional media slot for optional Media Basket(s), to customize your filtration needs.

Installation/Quick Setup Guide

  1. Verify Model. Includes BIO-Wheel Cover, Filter Cover, Impeller Housing, Impeller, Intake Tube, Mid-Level Intake Strainer, Extension Tube, Strainer, BIO-Wheel(s), BIO-Wheel Bearings, Filter Box, and Filter Cartridge(s).
  2. Install Filter Cartridge(s). Rinse filter cartridges thoroughly and install with blue side facing back of filter box. BIO-Wheel should rest securely in BIO-Wheel Bearings.
  3. Assemble Intake. Attach strainer to extension tube and insert extension tube into mid-level intake strainer. Attach mid-level strainer to intake tube and insert intake tube into impeller housing.
  4. Install and Fill. Install Power filter on back of aquarium frame before adding water to filter box. Fill filter box with water. Replace BIO-Wheel and filter covers. To start your system, just plug in. Adjust intake if desired.

Replace filter cartridge every 2 to 4 weeks. NEVER clean or replace BIO-Wheel. Discoloration of material is normal and desirable. If excessive buildup occurs, rinse gently with dechlorinated water (room temperature) as needed. Extra media slot is for inserting additional filter cartridge or adding other filtration media.

Troubleshooting Guidelines
Symptoms Comments/Solution
If your filter fails to pump water or flow has slowed...
  • Make certain the power outlet is functioning properly. Unplug electrical cord momentarily, then reconnect to power source to restart the impeller.
  • Check to make sure Impeller Housing is firmly seated in Filter Box and that water is at correct level.
  • Remove Impeller Housing and make sure Impeller Assembly is free to rotate. A particle of carbon or gravel may be interfering.
  • Inspect aquarium water level. Maintain at least 1/2" below top of frame.
  • Clean inside of Intake Tube with flexible filter brush.
If your filter makes excessive mechanical noise...
  • Make sure the Impeller Housing is firmly seated in Filter Box and water is at correct level.
  • Remove Impeller Housing and make sure Impeller Assembly is free to rotate. A particle of carbon or gravel may be interfering.
  • Replace worn Impeller Housing or worn Impeller Assembly.
If air does not evacuate from system...
  • Check for crack in Intake Tube and replace if defective.
If your BIO-Wheel splashes and/or makes excessive water noise...
  • Allow 24 to 48 hours for "breaking in" period. Material in BIO-Wheel is not fully absorptive when new.
  • Check aquarium water level. Lower than normal levels can result in excessive splash or noise.
If your BIO-Wheel fails to move or stops...
  • Inspect the BIO-Wheel Bearing and Axle for dirt or mineral deposits. You may need to clean these areas carefully.
  • Make sure all parts are installed properly and that nothing is blocking BIO-Wheel.
  • Examine the Intake Tube for flow interference.
  • Lift Filter Cartridge and check for blockage.
  • Perform regular filter maintenance.
If your BIO-Wheel becomes discolored or dirty...
  • This is not a problem. It indicates the growth of beneficial biological bacteria, which remove toxic ammonia and nitrite from aquarium water. Do not attempt to clean BIO-Wheel pleats.
  • As long as BIO-Wheel is not damaged, it does not need to be replaced.

Penguin 350 Review:

By Kmuda


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... and even then, you might not find an HOB that is any more quiet. (Note: My Penguin 200 is the quietest HOB I have ever owned. The 350s are not as quiet.)

  • 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.

Posted: 3 years 10 months ago by shaleeon #46271
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How much is a penguin 200
Posted: 5 years 9 months ago by kmuda #13
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I recently purchased a Penguin 200 as a secondary filter on one of my 55 gallon tanks. I'm very happy with it. I was surprised at how quiet it is. The last Penguin 350 I bought has a habit of getting a bit loud for a filter. Not so with the 200. As quiet as it can be.