Since the original whisper filters were released, there has been some complaints about the impellor system of the filter.  The impellors often will seize up and stop turning.  It is easy enough to get them going again, typically you can pull the impellor out of the unit and drop it back on which the unit is plugged in and the impellor will start up again.  I've run up to 7 Whisper filters simultaneously, and 6 of the seven exhibited this behavior every time I unplugged the filter and then plugged it back in.  While this is a minor fault of the typical whisper filter, it becomes a major problem with the TetraTec filters.

Since the TetraTec filters have heaters in the filter, an impellor that seizes will cause the heater capsule to be left out of water while over-heating.  Over time, I believe this will lead to the heater cracking its glass. (author's note:  while some heaters state on their packages that they will not crack even if left plugged in out of water, most heaters will break if left out of the aquarium.  The TetraTec heater unit itself contains no statement of it being able to be out of water without damage to the unit, so I am assuming it to be like the majority of heaters on this point.)  To combat this, you will need to clean the impellor out at least monthly.  For most hobbyists, that is far too much maintenance.

In addition, I found the set-up and daily running of the heater to be too difficult.  In order for the LFC to function properly, you must let the filter run for several minutes.  You then adjust a dial in the filter to set water flow into the LFC.  Setting the water flow correctly will make the LFC fill and empty very regularly until the water level in the aquarium drops substantially.  The process takes typically 5-10 minutes when the filter is first set up, and then another 5-10 minutes a week later as the water level drops in the aquarium. (Due to the splash created by the LFC surge, I found water levels in aquariums with this filter will drop quicker than normal)

The LFC creates A LOT of noise as it discharges the water through the chamber.  The good thing about it doing this is that you can easily tell by listening to the filter if the LFC is working correctly or not.  The bad thing about it is that it is quite noisy.  If you have ever been to a public aquarium and seen a tide pool tank, then you should have a concept of how this sounds because it is the exact same concept miniaturized.

To its credit, the heaters used in this unit have very thick glass.  They are shatter resistant, and for a good reason considering the impellor seizing I've had with this and other Tetra power filters.  The filter intake tube is made of less durable plastic than the original whisper filters.  It will not survive if you accidentally step on it.  Since the filter intake tube has a heater plug right into it, it is quite large and hollow, making it easy to break if you handle the brittle plastic incorrectly.  Still, as long as you never leave it lying around, I believe it should work for quite some time, perhaps 5-10 years.

The filter is intended to provide competition for the Bio-Wheel filters which have come to dominate the market in the last 10 years.  The LFC in this filter is made to provide better filtration than Bio-Wheel, through a large bacterial bed that receives maximum oxygen.  Bacteria that receive more oxygen (up to a point of course!) do more work in breaking down harmful chemicals in the water.  The only problem with the set-up in this filter is the extra effort needed to ensure that the LFC is functioning correctly.  Typically it will need to be adjusted every 1-2 weeks, or the LFC will stop pulsing water through it, defeating the entire purpose of the chamber. 

When running, the LFC provides water filtration as well as, if not better than any filter on the market.  The only problem with the quality is that on average, I found the LFC not to be functioning correctly and thereby providing a lower quality of filtration than most filters available.  If I was to rate the filter on its quality when working correctly without considering anything else, I would give it a 10 in this category.

"This filter does a good job of cleaning, but it requires far too much effort on the part of the aquarist in order to make it work correctly. For my money I’d recommend any other power filter before this one." I initially said that about the Wardley SandMan filters, but I believe that to be more fitting now of this filter than that one. 

In my opinion, this is the worst filter on the market today.  It is far too expensive, nearly double the price of a Bio-Wheel, and on average, it provides lower filtration than other filters on the market.  Some other negatives that I haven't discussed yet include the ridiculously large size of the unit and potential for disaster.  When I set up the filter on a 25, as it was built for tanks up to 30 gallons,  I was unable to put my tank top on correctly as the filter hung so far into the tank that there wasn't room. 

However, I found something I believe to be far worse than that which plagues this filter.  Every filter has an overfill, so that if the filter clogs, it can dump the water back into the tank instead of creating a large mess.  Typically if you replace your filter pads at least every 4 weeks, the pads will not clog, and you will not ever see water coming back into the tank through the overfill.  However, most people don't replace their filter pads every 4 weeks.  This filter features 2 filter pads.  While I initially thought that was a good idea, it proved disastrous.  When both my pads clogged, the overfill was not nearly large enough for the water that needs to go over it.  I had to clean several gallons of water off of the floor that had overflowed off of the back of the filter.  I have been in the hobby 20+ years, I have 35+ aquariums set-up, I have power filters on nearly every one of those tanks.  I have never, ever before had a filter overflow onto the ground.  If this had happened while I was out of town for a week, the filter would have ruined my floor by dumping 10 or more gallons on it, not to mention the likely impact on the aquarium's inhabitants. 

While it may be the case that my experience was out of the ordinary, I cannot in good conscience recommend this filter/heater combo to anyone.  I think the heater setup combined with the impellor seizures make it a likely hazard to itself.  The poorly designed overflow makes it a hazard to your floors.  The bulky size makes it hard if not impossible to use with many tank top sizes.  The price is also far more expensive than any other filter of the same size that is on the market today.  I strongly recommend against this filter and suggest you look to other filters available on the market to meet your filtering needs..

On a last note, if you do decide you must have one of these filters, I would recommend that you do not purchase the heater capsule.  The heater capsule itself costs much more than far better heaters made by Ebo-Jager and MarineLand.  The filter works fine without the heater, in fact, I would suggest it is less stressful to run as you do not have to be concerned about what will happen to the heater if the impellor seizes and all the water in the filter drains back into the tank.