This is a great HOB filter. It's fairly quiet and cleans excellent. I wouldn't recommend any other HOB filter. A little on the pricy side but easy to clean and works like a charm. I've had it up and running for over a year, my friend had it up and running for 3 yrs. That's 4 yrs and I never, ever had a problem with it.

The Emperor 400's push a huge amount of water with NO bypass. There is a huge area to put in whatever media type you want.The plastic the Emperor's are made of is not a flimsy plastic that can crack easy like the Aqua Clears are made of. The spray bars on the Emperor's work great, other HOB's do not have the spray bars. Some will say they are too load, all they need to do is adjust the intake tube and the Emperor's are quite.

I've been using these filters for several years, and they truly are the best. If used correctly, these filters will keep your tank(s) crystal clear. The extra media basket allows for so many different options, and when combined with the "E" cartridge this filter is phenomenal. Remember to clean the spray bar monthly to get maximum wet/dry filtration from your unit. Emperor filters are the best, work the best, and should be used by serious hobbyists looking for the best filtration.

One of the best HOB filters I have owned. Keeps my tank healthy, clean, filtered, and well maintained. It also has a bio-wheel driven by a spray bar which acts as a mini biological filtration untit. I couldn't have owned better filters.

Decent filter but just really way too loud. I don't believe biowheels are really necessary for a clean fish tank and this filter is really just all about the biowheels. Otherwise, you are just getting two little cartridges which are expensive to replace. The filter is also much much bigger than you might expect. The noise factor kills it for me. Marineland sent me another impeller and the noise issue didn't improve. I would stick with their standard line of penguin biowheel filters and skip this one.

I run Emperor 280's on my 29g South American and 38g Mbuna tanks.
They were my first filters, and as a novice I have to say that they were incredibly easy to set up. They both run relatively quietly, but I like a light gurgle in the room - your tastes may vary.
I don't find that the filter cartridges last very long, but the extra cage can be stuffed with filter media of one's choosing - that cuts down costs since the fancy blue floss and carbon aren't needed.
One of my 280s splashes around a bit as water comes out of the intake tube - so much so that I had to build up a mini wall to keep it from dripping down the outside. One night of unforeseen dripping left about 5 L of water on my carpet.
My other 280 needs to have the filter box topped up during water changes or it just won't restart properly.
Both issues were easy to resolve, but my next tank will have canister filters.

I have had mine for about four and half to five years...never really had a problem with it...the only thing I have to compline about is that the spray tubes that make the biowheel move always gets cloged so the biowheel does not move and it kind of noisy I have mine in the living room and I can hear it all the way to my bedroom which is pretty far...other than that it does a very good job on my 60 gal african tank which has been crowed off and on with big fish....

The main complaint you will hear from people on here is that the replacement filter pads are expensive, and they are right they can be, but all you need is a little imagination. Just scrap the proprietary pads and get some bulk filter pad sheets and cut it to fit the extra gray media tray. And the idea of people saying the media clogs too fast... It is because it's a no bypass system! Anyone who is happy because their filter never clogs up... Well they are daft. It never clogs up because it is not doing it's job! Simply put they are the best HOB filter you can buy. I have one on a 29g tank with quite the colony of Julidochromis Marlieri Gombi's. And the water is crystal clear and tests exellent.

I used to be a big fanboy for these filters but over time and experience I have to come to realize that there are better choices. Marineland will sell you on the biowheels - you get a wet dry filtration capability in a simple HOB filter. Yes, it is a good design and I am sure it's effective - but in truth no properly stocked freshwater aquarium would require this feature. Especially if your tank is heavily planted as not only does it's remove CO2 from the water, it also forces the plants to compete harder for the ammonia since it provides such a good home for large bacteria populations. Plus the biowheel causes more evaporation. And in the winter or in dry climates, that means you have to top off more often.

But speaking for the filter itself it's a decent quality unit. The cartridges fit very snug and I am of the feeling that there is far less bypass with these than with Aquaclears or Whispers. But the downside is that these cartridges are pricey, and they don't last terribly long. (I've actually had two of them disintegrate when I tried rinsing them off for reuse.)

The lack of flow control is another downside. As is the often difficult process of restarting them after maintenance. My 400 can sometimes have me going bonkers with its inability to get flowing.

Though all in all, these are probably the most effective HOBs as far as cleaning the water is concerned. Though that makes for their favor, I have to say the cons sure do add up.

I own the Emperor 400 and it is on a 40Br. It works O.K. on this size tank but I probably would not use it on anything larger than a 55g. Its not quite as easy to maintain as other HOB filters. The Bio-wheel justs is not as effective as the ceramic ring type media. The filter is also a bit overpriced for what you get.

I've only owned penguin and marineland but I do have friends and family that own other HOBs. In my opinion they are all pretty much the same, but I would still not trade my emp400 for any other filter. It is easy to maintain, has 2 additional media baskets that you can fill with anything you want. It's been 3+yrs and I haven't had an issue with it. Great filter.

I have 2 emporer 400's on a 150 extra tall. they worked great when the tank was just set up and the fish were small. But cannot handle the larger bio-loads of the larger fish. The Lack of media in these filters deffinetely doesnt help. The bio-wheels are EXTREMELY OVER-RATED! Too much water can go around the media with all the unused space in the filter. Tank was always cloudy because it couldnt handle the bio-load, and the water would turn yellow after 3 days of a water change because of lack of media. I suppose it would be a decent filter for a 75 gallon or smaller. anything bigger dont waste your time.

Like the previous poster I use two 400s with a XP3 on my main tank, and find the 400s to be excellent filters. Maintenance is easy and you can with proper care use the same cartridge for several months. I recommend adding some filter floss in the provided media holders to enhance the mechanical filtration. You can also spruce up the bio filtration if you follow the directions in the article about them on this site, though I didn't see a need to.

I have been running two of the Emp 400's along with an XP3 and two 1140 powerheads on my 125 for a little better than six months and they do a good job. They aren't the quietest filter around and they could be improved but I like them better than the whispers I use on my 75.

Don't get me wrong, this is a good product. It keeps the tank clean, and the bio wheel does in fact build a large, hungry bacterial colony. The supplied empty grey frame is great for installing chemical filtration media. The 400 model keeps a 72 gallon bowfront clean. But the filter could be improved:

1. Like many hang on back filters, it could be a bit quieter.

2. The bio wheels need frequent attention. Snails jam them and must be removed.

3. As good as it is for bio and chemical filtration, it is only average for mechanical filtration. If there were more mechanical media (more or bigger pads), this would be a great filter.

To solve #3, I've taken to stuffing the grey chemical frame with cheap polyester pads, and placing them in front of the MarineLand cartridges. This adds the missing mechanical filtration, and extends the life of the Marineland cartridges (particularly for a big tank).

The noise is not bad, unless you try to use it in a bedroom, like another reviewer said.