Throughout my years of fish keeping, I've tried the most popular filters. When I first started, I had the following...
UGFs (Under Gravel Filters) - They are good biological filtration, becuase the substrate (from top to bottom) provides the biological filtration. Their are UGF plates underneath the substrate and with the use of a powerhead, water is drawn from the surface of the subtrate through the bottom, oxygenating the nitrifying bacteria. It is considered as a simple, beginner type of filtration, IMO, they are actually more for the experienced, who maintain a cleaning regiment. It is a great filter, since there is no media to change. Unfortunately, it must be properly for it to function well.
HOB (Hang on Back Filters) -I moved up to a
Marineland Emperor (400 & 280) HOB filters, due to their popularity as a great biological filtration, due to the added biowheel. They also offer good mechanical and chemical filtration. The filter pads came with carbon media, so you had mechanical and chemical in one pad. There is also an additional tray, which you could fill, for added chemical or biological filtration. I normally cleaned out the filter pad on occassions, even though the carbon is no longer useful, so I basically made the carbon media portion act as an additional surface for nitrifying bacteria to colonize. The Emperor biowheels perform better than the Pengiun Biowheels, since the Emperors wheel turn by an additional spray bar over the biowheel. The Pengiun biowheels are turned by water flowing underneath the wheel, which at times is not strong enough to turn the wheel, therefore, the wheel doesn't function.
I used to use the Emperor 480 on my 55 gallon tank, Emperor 280's on my 37 gallon, 29 gallon, 20 gallon, and 20 gallon long tanks.
I just recently purchased a
Hagen Aquaclear 20. which I use on my 10 gallon tank for my L046 zebra juvenile plecos. It's very popular filter, which contains various medias to make it as a mechanical, biological, and chemical filtration. Although, I only use sponges for mechanical and biological filtration. It's one of the most popular filters used by majority of the people in a planted tank forum I belonged to. I wanted to give it a try on my smaller tank to see how well it functions. So far, I am pleased with it.
Canister Filters - After my experience with the Marineland HOB filters, I decided to move up to one of the most popular canister filters, Eheim's. I purchased the
Eheim Pro II 2128, which came with a built-in heater. Canister filters are good, becuase it allows you to switch the media to your liking, to better aid in mechanical, biological, and/or chemical filtration. You do not have to use same brand media as the filter. I can use Hagen media in my Eheim canister filter if I choose to. I normally place a sponge pad, for mechanical filtration, then fill majority of the trays with ehfisubstrate for biological filtration, and filter floss for additional mechanical filtration, which traps the smallest particle.
There are many types of canister filters. Eheim's are the most popular brands. They are considered to be the porche of canister filters. I recently purchased
Eheim Eccos, which are lower grade Eheim filters, but still function well. I use the Eheim Ecco 2236 on my 55 gallon tank, 2234 on my 29 gallon tank, and soon a 2232 on my 20 gallon tank.
I also purchased a
FilStar filter, which is another popular brand, next to the Eheim filters. They are allot cheaper than the Eheims, but appears that it is a little cheaper construction than the Eheims. The filter does have stronger GPH than than the Eheim, but from my experience, when the FilStar gets clogged, their is a drastic slowdown in flow. The Eheim does not.
With all the canister filters, with the exception of the Eheim Pro II 2128, I also use a
Hydor Inline Heater, which are very popular heaters, since they are not contained in the tank, but inline with your canister filter tubing. Therefore, you do not see the heater in the tank and your fish are protected from accidently touching the heater and getting burned.
In conclusion
All the filters work well, as long as they are maintained properly following with good tank maintenance. IMO, I like canister filters, becuase they are easy to maintain and you are not forced to use the same brand media as the filter. You can even use very small, inert rocks from you backyard to put in the media tray to act as a biological filtration. You can also use any generic filter floss, as well, which is what I do. You can also add additional equipment inline to the canister filter, such as a heater, UV filter, pH probes, inline so they cannot be seen inside the tank.
With HOB filters, you are forced to buy their brand of filter pads, since each design of the filter pad is spefically made for that type of HOB filter.