Should I Use An Under-Gravel Filter?

Another "How-To" By Jeff Snyder...and he ought to know! :)


Whether or not you use a UGF -- or under-gravel filter -- in your aquarium
is really a personal choice. While many new types of filtration systems --
such as wet/dry systems, protein skimmers, canister filters, hang-on
filters, etc. -- have been designed over the past four decades since I set
up my first twenty-gallon tank, it is important to remember that for many years, tropical fish hobbyists relied solely upon the "lowly" under-gravel filter -- and internal box filters with charcoal and floss -- to maintain healthy fish and aquariums. In fact, before the arrival of powerheads, UGF's were powered by airstones and an air pump; which to some modern aquarists,
must seem like ancient technology -- and I don't mean the Ancients from Stargate either! Of course, with the arrival of powerheads, it became
possible to use under-gravel filters even more effectively and efficiently
than ever before.

While under-gravel filters have been a reliable means of aquarium filtration for many years, they do possess a few drawbacks as well. One of these is
that as detritus -- in the form of uneaten fish food, fish feces, etc. -- collects in the gravel bed, it becomes a huge nitrate factory. As all experienced aquarists know, high nitrate levels stunt fish growth, and can
lead to other fish maladies as well, including death.

Of course, if one is faithful to perform weekly water changes, as well as to vacuum the gravel on a regular basis, the nitrate can be maintained at a tolerable level. The problem is that many new tropical fish hobbyists are
not even aware that these things need to be done. Furthermore, as a result
of their busy schedules, even experienced aquarists often neglect these important tasks. As a result, the detritus continues to build up in the
gravel bed week after week, and month after month, all the while feeding the nitrate level. It isn't until the poor fish become sick and start to die,
that some hobbyists realize that something is dreadfully wrong.

Another problem with under-gravel filters is that over time, the substrate
-- or gravel bed -- can become packed in places. If this occurs, the flow of oxygen-rich water -- which sustains the good bacteria known as nitrosomonas
and nitrobacters -- can be impeded. This may result in the formation of
pockets of anaerobic bacteria; that is, the "bad" bacteria which don't like oxygen. Anaerobic bacteria can produce hydrogen sulfide gas, which is lethal
to your fish. If you smell rotten eggs in your tank, you probably have a hydrogen sulfide problem, and you need to address it immediately.

When I set up my 45-gallon mbuna tank again this past April, I decided to forego using a UGF, and just laid down a sand substrate, over which I built
a rock pile full of tunnels and caves from one end of the tank to the other. All of the large base rocks sit on smaller support rocks, which sit directly
on the glass bottom. This allows water to flow under and all around the
rocks. As for the sand, my fish are constantly moving it and stirring it up,
so there are no anaerobic pockets as far as I know. Between my filtration system -- which currently consists of two Penguin 330 Bio-Wheels each
powered by a Penguin 1140 powerhead -- and weekly water changes of 25% or
more, my nitrate level has been very good at 0 to 12.5 mg/l. In fact, I
never saw it that good in an established tank when I was using UGF's. In my view, the reason for this improvement in the nitrate level is obvious --
there is a lot less organic debris being collected in the substrate.

In addition to not using a UGF, I also use my turkey baster technique --
please see my post entitled [b]How To Clean Up Detritus[/b] -- and I also
stay on top of making sure that the filter pads in my Penguin filters don't become excessively clogged.

In conclusion, regardless of what type of filtration system you use with
your aquarium, the key to success is consistent daily and weekly
maintenance. The best filtration system in the world is useless, if it is
not properly maintained, and there are no shortcuts for that.



Jeff Snyder, SysOp - Armageddon BBS Visit us at endtimeprophecy.org port 23 ---------------------------------------------------------------------------- Your Download Center 4 Mac BBS Software & Christian Files. We Use Hermes II


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