underwater gravel filters

Question
Karen,

Would you share your thoughts on UWG filters. After keeping over 300 gallons of fish some 15 yrs ago, I have found the passion again to keep freshwater fish.

I have read some disturbing things about the UWG filters, especially about the large beneficial bacteria colonies depleting the oxygen levels in the water and "gunk" that accumulates under the plates after some time which raises the nitrate levels in an established tank after time.

I always filtered my tanks with power heads in conjunction with an UWG filter and the HOB type power filter. Always worked in the past but I am willing to use what ever is best in your opinion.

Thank you in advance

Answer
Hi Dirk,
You've already discovered the answers I have about Undergravel filters. The risk of anerobic bacteria and "gunk" collection producing excess pollution is quite high, especially in a well stocked tank. For a simple aquarium being lightly stocked, this probably wouldn't be much of a problem, but few people have such a setup and undergravel filters just tend to cause more trouble than benefit.

And with the wonderfully advanced filters available today, its only logical to use them. I am very fond of the hang on the back (HOB) power filters which both provide good areas for beneficial bacteria, clean suspended particles very efficiently and aerate the water very well with the added plus of being extremely easy to clean. Just take out the cartridge and gently rinse it in a bucket of tank water. That's all that is needed. No mess or time consuming cleaning.

My next favorite filter is the Sponge filter. It is more of a biological filter though but it still works great in many tanks, including lightly stocked aquariums, and its best reputation is being used so successfully in fry tanks. It has no dangerous impellers or anything that would harm fry and the sponge provides an immense area for beneficial bacteria other microscopic organisms that many fish like to feed on. "Seasoned" sponge filters can be added to a newly setup tank and "instantly" cycle it. I've done this many times before and a lot of fish keepers are aware of this miracle solution to new tank syndrome.

I hope this helps and best of luck!
Karen~