The Emperor 400 hang on back (HOB) power filter has 4 media bays and 2 bio wheels. The box instructs you to set up the filter using 2 bays for mechanical filtration, 2 for chemical filtration, and the 2 bio wheels for biological filtration. This gives you access to all types of filtration in one easy to use set up.
The Emperor 400 is rated at 400 gallons per hour (GPH).
Positive features:- Bio Wheels are what make these filters what they are. Wet/dry filtration is considered by many to be the best option for biological media and the Emperor 400 gives you this option in a smaller HOB filter without needing to set up a sump. They provide an ideal place for beneficial bacteria to colonize. Bacteria need food (ammonia and nitrite) to survive and your filter passes this by the bio wheels continuously. They also require huge amounts of oxygen. Most filters suffer from having to rely on the dissolved oxygen in the water but bio wheel filters have access to the oxygen in the air. Oxygen levels in the aquarium generally run between 7-8.5 ppm while oxygen levels in room air will run upwards of 200,000 ppm!!!.
- Relatively easy to clean and maintain
Negative features:- Spray bar on Emperor 400’s sprays unfiltered water on the bio wheels. This is meant to keep them wet and to have direct access to oxygenated water. The water does not pass through any mechanical media however and can be a cause of gunk build up on the bio wheels which will effectively decrease the surface area available for bacterial colonization. Simple maintainance will prevent this however. The spray bar also tends to build up with gunk which will limit the water flow.
- If the impeller housing builds up with gunk it will significantly limit water flow through the filter and it can build up relatively quickly. Again simple maintainance will prevent this from happening.
Modifications or Tips to Improve Performance:- I purchase a course padding from a fabric store and cut it into sections to fit into the media trays. I also purchase fine quilt batting and cut that into pieces that will fit into the Chemical Media Baskets that come with your filter. This costs a fraction of what it would cost to purchase the pre made filters that Marineland sells. I place the course pad in the first media bay, the quilt batting in the basket in the second media bay and this gives me a two level course to fine mechanical filtration.
- I’ve found that it’s best to clean the impeller housing and spray bars about once every 3-4 weeks for best performance and to wipe out the filter about once every 3 months.
I would highly recommend the Emperor 400 as either a stand alone filter on tanks up to 40 gallons or as part of your total filtration. Unless you have a sump with wet/dry filtration they are hard to beat for biological filtration and with the adaptations made above they serve very well with mechanical filtration as well. They are also one of the more powerful HOB filters on the market.
Photos By: johnl