Hang On Tank Magnum Pro System Canister Filter

Written by Kmuda. Posted in Canister Filters






  • Long life motor design with high energy ceramic magnet for corrosion-free reliability
  • Extra long cord (8 ft) for multiple task usage
  • Adjustable split flow diffuser (patent pending) for bi-directional water circulation
  • Sweepline intake/outlet tubes for greater flow efficiency and cleaning ease
  • Two-year comprehensive warranty


Lightweight enough to hang directly on the back of your aquarium, yet it does the heavy duty work of two complete filtration systems. And it's simple to set up, easy to maintain and readily portable. Sleek, silent, powerful... it's a triumph of no-compromise design technology.


The H.O.T. Magnum is actually two filters in one, perfect for everyday mechanical/chemical filtration and quick-clean water polishing. Its powerful self-starting pump silently directs a certified 250 gallons per hour through the advanced dual-flow core and sealed media, delivering total contact, total filtration, without bypass. Its hang-on-tank, easy setup design makes it ideal for multiple aquarium water polishing. Snap-lock, leak-proof connectors eliminate the need for hoses or tubing. And H.O.T. Magnum's UL- Listed synchronous motor and epoxy-encapsulated electrical components are your assurance of safe operation. The triple duty union of a classic wet/dry biological filter with powerful mechanical/chemical Magnum filtration. For aquariums up to 50 gallons.


H.O.T Magnum Pro System includes: H.O.T. Magnum Canister Filter, Micron Cartridge, Carbon/Media Container, Filter Sleeve, 8 oz Black Diamond Premium Activated Carbon, plus a BIO-Wheel PRO 30 Wet/Dry Biological Filter.


The benefits of Mechanical, Biological, and Chemical Filtration


Mechanical Filtration is the physical removal of particulate matter from the water. This is achieved by introducing a mechanical barrier in the water flow that traps particles of a certain size according to filter material used. A mechanical filter is only effective when it is cleaned regularly, otherwise bacteria will settle in and start breaking down the collected dirt, thus setting minerals free into the water as well as becoming a bio-filter resulting in increased nitrate levels.


Biological Filtration is the process by which aerobic (nitrifying) bacteria of the genus Nitrosomonas and Nitrobacter oxide, the toxic ammonia through nitrite (which is only slightly less toxic than ammonia), to the relatively harmless nitrate. This process is known as nitrification, and in nature, takes place in aquatic habitats and soils where ammonia and sufficient oxygen are present. The nitrifying bacteria develop naturally in an aquatic environment and will colonize any suitable filter media such as the Polystrand filter pads supplied in the Ocean Clear Filters. Once a biological filter media has been established, it should be disturbed as little as possible since the bacteria colony maintains its level of activity according to the bio-load present in the system.


Chemical Filtration uses chemicals, in particular Active Carbon, to absorb organic material such as oxidation products of proteins, remains of fish medications and organic toxicants. It is also effective in removing oxidation products that are formed by ozonating seawater (slight amounts of chlorine and bromine). Active Carbon should be replaced regularly, since it gets saturated and as bacteria settle on it, it will eventually work like an ordinary biological filter.


Maintenance: Frequent visual inspections of your filter are recommended. Unusual occurrences such as lack of water flow, excessive mechanical or water noise, cloudy or bad smelling water require immediate attention. To ensure best filter performance and maintain full water flow, regular cleaning and media changes are recommended, at least every 2-4 weeks.

These are the easy cleaning steps:

  1. Shut down system and remove canister.
  2. Change the media. Remove the media and rinse thoroughly, replace with new media. Remove the cartridge and rinse off all visible dirt. Your cartridge can be soaked in a solution of one part chlorine bleach and three parts water. Rinse the cartridge thoroughly until the bleach smell disappears.
  3. Clean air ejector tube with nylon cleaning wand (included).
  4. Clean canister thoroughly, especially sump area.
  5. Clean impeller module, gently squeeze sides to pop open.
  6. Clean impeller assembly and inspect for wear and smooth rotation. Replace any parts that have noticeable wear.
  7. Gently clean flat exhaust gaskets with warm water.
  8. Wash d-ring seating area on canister and cover. Wet d-ring before installing.
  9. Reassemble system and return to operation.

Never use soap, abrasive cleaners, or other cleaning agents on or around the filter or your aquarium.


Marineland HOT 250 Review:

By Kmuda


This is the little brother to the Magnum 350 with the added convenience of being a "hang on tank" filter. Although this filter appears to be somewhat of a "tweener", make no mistake, the physical dynamics of this little guy are those of a canister filter, which makes it more efficient than an HOB filter. I own two of these, using the same type of modifications I use for the Magnum 350s. One of these two has been in constant use since the early 90s.


This filter is comparatively priced with an AquaClear 110 (AC110). If selecting a secondary filter, I would likely choose this over an AC110 because it is a much more efficient filter, silent, and has the added flexibility of becoming a Micron filter whenever that extra water polishing is desired.


I have used this as solo filtration on a 40 gallon discus tank. If looking for a canister filter for a smaller tank, and you want the ease of use of an HOB filter or do not want the leak concerns of a standard canister filter, this filter is worthy of a look.


  • Made in the USA.
  • A very dependable filter. As mentioned, mine has been in use since the early 90s.
  • Very easy to work with, no mess maintenance, easy to move around
  • Because it so easy to move from tank to tank, it can be used for extra water polishing (using the micron cartridge) on multiple tanks.
  • The filtration dynamics of a canister filter with the convenience of hang on the tank.
  • Easy to set up, use, and maintain.
  • With Simple Modifications, along with the biowheel, is an excellent biological filter, either as a primary filter on smaller tanks or secondary filter on larger tanks.
  • With the Micron filter, is an excellent mechanical filter
  • No bypass design, same as a Magnum 350
  • Has a power button. Why more filters do not have on/off switches is a mystery to me. Makes perfect sense.


  • Filter is designed primarily for mechanical or chemical filtration, with the biowheel providing biofiltration. However, with this design, only a percentage of the water passes over the biowheel, which limits its effectiveness as a biofilter. You have to think a bit outside the box if wanting to use this as a biofilter. These Simple Modifications make this a great little biofilter.
  • There is only a single container for media, with this container designed primarily for activated carbon. I fill this container with Eheim Ehfilav or Eheim Substrate Pro for increased biofiltration. However, the amount of media that can be employed is limited when compared to other canister filters, but it holds more media than a standard HOB filters.
  • The "D-Ring" should be lubricrated with a quality silicone lubricant during maintenance. 

Other information:

  • If using this as a primary filter, or if wanting to increase biofiltration, refer to the links located in several places above for the recommended modifications.


Recommended Maintenance Procedure:

Note: The below instructions assume you are using the recommended modifications.

  1. Fill a bucket with tank water
  2. Unplug the filter
  3. Remove the biowheel from it's housing, shaking it out in the bucket of water, then place it back into it's housing
  4. Disconnect the biowheel from the filter
  5. Lift the filter off the tank and carry to the sink
  6. Unhook and remove the filter lid.
  7. Remove the black tubing and air diffuser tube (clear tube), rinsing the black tube in the sink, scrubbing with a toothbrush to remove slime
  8. I use a straight length of a metal coat hanger (snipped from the coat hanger with wire cutters) to clean the air diffuser tube (lost my "nylon cleaning wand" a decade ago).
  9. Remove the media container, separating the sponge padding from the container (placing it into the sink) and dump the media into the bucket of tank water.
  10. Swirl the media around, rubbing it against each other, to dislodge gunk that has built up.
  11. Rinse the sponge padding in the sink (I use the dish sprayer attachment), being sure to turn it inside out to get both sides.
  12. Using a q-tip, filter brush, or toothbrush, clean the impeller housing.
  13. Place the impeller back into the housing, then the plastic tubing (note, look at the hole sizes in the base of the plastic tubing, lining up the different sized holes with the associated "pegs" in the bottom of the filter casing.
  14. Remove the biomedia from the bucket, placing it back into the media container
  15. Slide the sponge padding back around the media container, placing the media container back into the filter
  16. Fill the filter with dechlorinated water and then place the lid back onto the filter, securing it with the latch
  17. Carry the filter back to the tank, reconnecting the biowheel
  18. Plug the filter back up