This is the answer to this question in your other thread:EmpPleco said:I don't really know anything about the subject, because I bought both of my tanks in kits that already came with filters. But what makes BioWheel and cannister filters so much better and more expensive?
Gunnie said:There is nothing wrong with HOB filters. I personally dislike them, but that is just me. The reason I don't like them is because they usually require filter media you have to buy and replace, they tend to lose their prime when the power fluctuates, and they can be a pain to clean sometimes. I can't tell you how many times I have come home and one of the HOB's is howling because there was a power surge and the filter ran dry. Since I was gone when this happened, I have no idea how long the filter hasn't been running, and if all my bacteria is now dead - not a good thought if you plan on taking any trips for a few days! I like my sponge filters because you just squeeze and rinse them in old tank water to clean them, they last for years, and if the power goes off, your bacteria is in the water and has a better chance of survival. They also start right up when the power comes back on, and they are excellent for fry tanks. I like my canisters because they usually have more gph than most filters, they require less routine cleaning than the HOB's and mine (filstar XP series) have never lost their prime when there's a power outage. I find them very reliable. Also, they sit under your tank where you can hide them. All you see on your tank is the intake and the hose.
Filters are a matter of personal preference, and each tank has different filtration needs. HOB's are used by some, and that is the only type of filter they use or want to use. I just don't personally like them, and will opt for a sponge or canister first if possible.