[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[APD] Open Top Aquariums

Hi Tony and all,
Tony said
>How far above your tanks do you hang your lights? I have been thinking
>of trying an open top and am wondering what the ideal distance would be.
>With no glass cover and lights too close would you then get light loss due
>deposit build up on the bulbs themselves and on your reflector?

I could go on for hours about how great I think open top aquariums are. I
think they are romantic in the sense that as soon as you remove the cover
glasses from a tank it becomes an intimate part of your living environment.
Looking at an aquarium from just the front glass is like looking at am old
B&W TV set as compared to looking at it from the top as well. Then it feels
more like a part of nature.

As much as I like open top aquariums they aren't very popular overall. I bet
at least 98% of aquariums are purchased with cover glasses. Not much has
been written about it either (at least I haven't found much to read about
it). Claus Christensen of Tropica wrote a nice little piece entitled "The
Open Aquarium" in the March-June 1998 TAG. If you are into biotopes they are
useful because of the possibilities of using emersed growth, which is 50
times more efficient than submerged growth, but then again most aquarists
aren't into that either. Takashi Amano is starting to explore a more
"natural" representation of nature and has mentioned stressing emergent
growth as a new dimension in aquascaping.

To start I've made a bookmark to a page that shows some of my lighting. Its
If that doesn't work go to the main web page at:
http://users.ev1.net/~spituch/         and drill down through "hardware/sun
room". The first thing you'll notice that my lights look cheap.

Once you take the cover glasses off of the tank, the humidity above the tank
will greatly decrease (thus evaporation can become a concern). But you no
longer get the distilled water condensation that etches the cover glasses
(or any deposits from say spray). My fluorescent light box on the 75 g tank
has been between 6 and 16 inches above the water. There is never any
condensation on it and it is dry in the underside of the box where the
lights are. I think the lights could be as low as one inch from the water
and you would still have enough ventilation around the sides to prevent any
condensation. However, to experience the true feeling of an open top
aquarium you need to be able to see and get to the water surface, so the
higher the better. I think anything at 3 Watts per gallon and above can go
at least 12 inches above the water and act the same as being on top of a
dirty cover glass. 175 Watt MH pendants are usually 12 to 16 inches above
the water.

Some people have tight cover glasses on their tanks. Unfortunately the CO2
can push all the oxygen out of the air space. The fish suffocate from no
oxygen, not CO2 poisoning. This has happened I recall two or three times to
people on this list. If you have an open top aquarium you conserve CO2 by
not having any aeration or strong surface movement of the water _"at the
surface"_.  I have all my filter exit spray bars pointed slightly downward
from horizontal. You can see the plants sway in the current, but you can
hardly detect a ripple in the almost glass smooth surface. The glass-smooth
water surface and the floating plants give the really pleasant sensation of
looking close up at a pond.

I think all types of lighting are adaptable to open top aquariums. However
some types of light fixtures may be a little difficult to utilize. I am
thinking of the narrow plastic fluorescent strip light enclosures. They can
twist so much that an end connected bulb could pop out of the sockets. My
fluorescent box fixture is rigid and the end sockets are close to the bulbs,
so I have never felt that the bulbs were going to pop out. I have never used
waterproof end caps either for the fluorescent bulbs. Somehow I think that
my suspended lights are more secure than lights on a cover glass. I have had
cover glasses fall into the tank. If you are hanging onto the lights when
this happens you could get shocked. Generally, when I am working on
suspended lights, my hands are up high away for the water. I sense the
danger is less if one ever did let go and fall into the water because my
hands have less chance of being near the tank. In either event it pays to be
careful. Also, use a GFCI. I think it was Tom Barr who was writing about
translucent end supports for certain light fixtures. I envision this would
allow the tank to be open top, but the lights would still be close to the
water. I don't know. Hopefully he will post a picture of his idea when it

Take a look at my web site, and then let me know what equipment you have.
Cover glasses are so confining. I wonder if once you try the open top
aquarium, you will you like it so much, like me, that you will never go back
to cover glasses, or whether this is just a quirk with me? I must have a
damaged "cover glass" chromosome in me somewhere.

Steve Pituch

Aquatic-Plants mailing list
Aquatic-Plants at actwin_com