"Richard Sexton" wrote in message
...
Is it just me or are these things essentially useless?
http://aquaria.net/articles/lighting/screwin/
Hi Richard,
Well I started off with a cube 10 gal tank, with 1 X 9W, then a little
later, 2 X 15W 6500K "cheapie" (made in Asia) edison screw CF bulbs over the
tank with dull metal reflectors.
I had Asian Ambula, Pennywort, Tiger Corkscrew Val., Florida Banana Lily and
Water Wisteria (Hygrophilia difformis). They did okay with 1 X 9W, but just
okay. They weren't really growing, but they weren't dying either. When I
added 2 X 15W the Asian Ambula had to be cut back after about 2 weeks, as it
started to grow out of the top of the tank. The Wisteria and Pennywort also
shot up and grew, in total, about 3 inches (~ 7 cm) each, although the
leaves were smaller than when I got them - about one month for this growth
in this CF lighted tank.
The Val. just melted and I lost one of three. I had substrate issues, to be
honest, and I was worried about algae outbreaks because the NO CFs had a
fair bit of green in the visible spectrum, even though they looked
blue/white.
It proved a couple of things to me, which have stood me in good stead for my
new 220L/50Gal :-
Substrate is important and so is nutrition (macro nutrients). I was lucky in
the 10 GAL in that the substrate was full of nutrients by accident, as it
was given to me by someone who didn't take care of their gravel properly, so
it had a lot of "Stuff" in it - eventually I worked out my high Nitrate
levels and low pH were the result of OTS because of this gravel.
This translated into the new tank as macro fertilisation in the substrate
via things called "Dinosaur Dung", which are phosphate and nitrate free
fertilizer balls available here in Oz, and weekly liquid fertilisation of
the water column with a micro-nutrient liquid fertilizer.
The substrate particle size and condition are really important - I notice
your substrate in the pictures looks a bit fine. My gravel in the new tank
is two layers - the lower one with the balls in it is 1.0-2.5mm grains and
the upper one which is thinner, is black and has a particle size of 3 - 5mm.
Some of the more sensitve "rooty" plants are in plastic pots with clay kitty
litter and DD balls, with the top layer gravel on top and others are just
stuck in the tank gravel - there is no difference I can detect in root
formation or health in using either planting method btw.
The main thing I am trying to say is that substrate health, compostion and
macro fertilisation are probably more important than the light spectrum
itself.
Lights: I am now switched over to 2 X 36W 4 foot T8 tubes - One Philips
Aquarelle and one Chinese "plant spectrum" tube which was on sale at LFS#1.
The Philips is pink (10,000K) and the plant spectrum is 5700K and blue. I am
guessing the intensity is far greater from these T8 tubes, but maybe not in
comparison to the 10gal tank because this tank is deeper than the cube.
My point here about lights is that whilst spectrum and CRI are important to
plants, it's actually the intensity and period which plants respond to.
I also now have 15-20ppm CO2 happening, stable pH at 6.8 and sufficient KH
(5dKH/89.5ppm) and these tube lights are on 12 hours per day on a timer.
I have had both a diatom and green velvet algae outbreak recently, but the
diatom thing was NTS and has now gone and the green was from two things:
over feeding the fish and over fertilising. That is also now gone, as I've
cut back on the fertiliser and food and once all the damage to plants and
diatom infested leaves were pruned off, I now have regular day-time pearling
and robust fast growth on all plants.
I noticed also the surviving Val. had shot off runners and the leaves don't
melt any more. The Banana Lilies went absolutely beserk and covered the
water surface with pads, so I've cut them all off, and they are both
shooting up at unprecendented rates yet again - I swear you can see these
things growing - they go about and inch a day atm.
The Asian Ambula got really badly affected by the diatoms, and I just cut it
back really hard, about 2.5 cm above the substrate and in three-four weeks,
it's now about 1 cm from the water surface - so that's grown 46cm (1.25
feet) in ~28 days, which is astounding - what's more it's new growth is
nicely spaced between the nodes (sufficient light) and it's a really nice
healthy green. I have 4 X SAE's and two lyer-tail swords which "suck" any
algae off the leaves and a large Mystery Snail which has a go too.
So, sorry for the long story, but I'd suggest that you look at your
substrate, think about CO2, fertilisation and have think about light
intensity and period rather than suspecting a particular light type. A CF
IMO, isn't as efficient as a straight tube and that's just the shape and
dependent on application
I can't say the CF lights were anything but educational in my experience.
One thing - I never had an algae infestation with them, or any sort of light
related problem, which I did expect because of the predominant green in
their spectrum.
There is always the option of silk plants if all this aquatic gardening is
too much
It's crossed my mind at times, but you can't beat pearling real
plants in my experience and I don't know about you but I get a sense of
accomplishment when my aquarium plants are vibrant and healthy.
I will say one thing - it appears to be harder than terrestrial gardening in
my experience
All the best,
Oz
--
My Aquatic web Blog is at
http://members.optusnet.com.au/ivan.smith