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Re: NFC: Another Filter/Aquarium Question

Chris Hedemark wrote:
> Hey people should use whatever works for THEM.

Amen to that. 

Let me share a little under-gravel filter (UGF) trick that I learned from my
Betta friend Lew Heifner.

I have liked under-gravel filters from way back in the 50s, when we actually
thought they eliminated the need for water changes. :-) Oh well, times
change. We learn.

Folks who do most fancy planted tanks don't seem to like them at all, but
they often consider the fish a secondary nuisance to their aquatic gardens.
In my case, I primarily keep fish, but do enjoy dabbling with plants, too.
Their benefit to fish is such that I don't even keep fish (or
water-gestating eggs) in containers without any plants, even if it is just a
big wad of Java moss.

OK, OK, get to the trick.

Running undergravel filters with an air lift can be greatly enhanced by
putting a lamp underneath the tank, running for 24 hours a day. It warms the
gravel bed and promotes the growth of algae. Algae, unlike vascular plants
that must respirate to grow, prefer 24 hour light, so they grow lushly under
the filter plates, if illuminated constantly.

In a normal UGF (or any other biofilter), the nitrogen-converting bacteria
in the gravel are competing with the fish for available oxygen. Even with an
air-lift return, and particularly with a power-head pump, the water is
severely oxygen depleted by the biofilter. By adding the light, the
under-filter algae grab the excess CO2 given off by the oxygen-using
bacteria and dump copious quantities of oxygen into the water, day and
night. It's almost like a hidden wet-dry filter.

The lamp warms the gravel, which is a big benefit to the plants. The lower
reaches of the gravel in many tanks can be several degrees colder than the
main water column, and that's not at all natural for tropical plants. The
warmth probably promotes the biofilter action, too.

The amazing thing to me is that this trick seems to nearly eliminate
unwanted algae in the upper part of the tank! Since a lush growth under the
filter is grabbing all the most algae-needed nutrients, 24/7, and the
regular on-off daily cycle of the hood lamps isn't particularly favorable to
algae, what I see is clear, lush plant growth above, and a total green scum
when viewed through the bottom glass.

The big benefit to fish is the more rapid removal of any ammonium/ammonia
(algae grabs any the biofilter passes), and a major increase in dissolved
oxygen. The benefit is particularly apparent with very hyper species, with
high respiration rates, like Lampeyes and Rainbows. It surely should improve
the growth rate of any other fish, too.


Wright Huntley, Fremont CA, USA, 510 494-8679  huntleyone at home dot com

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Habit is a powerful force, and we no longer feel as intensely as we
once would have [the] constriction of our liberties that would have
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