Re:Outdoor tub ponds

["Malta Dairy Products Laboratory" <labmdp at waldonet_net.mt>]

For the normal Tropical Aquarium plants most of us talk about in this list,
one should avoid direct sunlight for more than a couple of hours a day. The
light and other radiation in an aquarium even at 5W/ gallon is much much
lower than direct sunlight (no cloud cover) in summer at noon .

If it is these tropical plants that you want to grow in a pond than shading
is necessary. The green netting is good. But I prefer the more natural
approach. I have a few palms round the pond and the light that passes
through their fronds is quite like the natural lighting most of the aquarium
plants have at home. They also reduce the heat arriving at the pond. You can
also use other trees or shrubs but make sure that they do not loose their
leaves easily.

Some diurnal temperature variation is natural even in the tropics. With
temperature fluctuations, it is not the volume which counts but the depth,
but if it is too deep you won't be able to see the life.  IMO 15- 30" is
good.

Floating plants don't help much in preventing heat entry, and they reproduce
at a phenomenal rate, cutting out too much light for the other plants. They
also prevent seeing the submerged plants so I avoid them. Lilies are good
for large ponds when you look horizontally, but for aquarium sized ponds you
want to look at the submerged life from above. Anything that detracts from
the view should be removed.

regards
Stephan
Malta

"Since the topic is up, I thought I'd ask... If I'm wanting to do tropical
fish outdoors in a tub during the summer what would be the minimum size
from a temperature stability standpoint? I was thinking at least fifty
gallons at first, now I'm wondering if eighty to a hundred gallons isn't
more realistic.

I don't want to take up the *entire* back patio if I don't have to. :-)
Anybody have some thoughts?

BTW, last summer I tried a twenty-gallon tub with water plants (no fish).
Some Salvinia got in there and grew over the entire top two layers thick.
I still had Rotala rotundifolia and Mayaca fluviatilis growing like mad
underneath it. The tub was got pretty much direct sun most of the day...
Despite what all those people with 5 wpg tanks might make you think, most
of those aquatic plants don't seem to be really direct sunlight type
plants. (Water lilies and floating plants seem to be the exception.)

Just my experience. I've only done it one summer, so what do I know. :-)
YMMV.

William"