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[APD] Re: Minimum light
1# I think you need to be specific with which species of plant needs a minimum amount of light. Hydrilla needs 12 micromoles/m^2/sec(full sun is about 2000). Not much.
Most aquatic plants have very low light compensation points(LCP).
If you provide non limiting conditions and this includes CO2, you will find this lowers the LCP significantly.
So 1 w/gal will work fairly well at 24" depth with pearl grass and PC lighting.
A 10 gal will do fine with a single 15w triton and CO2.
If you want to grow anything your heart desires, 2x15w will do nicely.
The watt/gal rule thingy:
Good for most general stuff using Fluorescents as the stanhdard, PC's, incads, MH's can be adjusted with a conversion factor simply.
I've grown enough plants and at enough depths to know what I can get away with, but before anyone goes and balmes the lights or the intensity etc...............you NEED to get the CO2/nutrients down first.
Yes, you can add more light than your plants need and perhaps get away with it and get the results you want, BUT and this is a big BUT, your chances of algae are HIGHER if you chose to go this route.
Experience can teach you a lot, simply trying things out will tell you but you also need to make certain is _not_ something other than the variable you are testing for when you make an observation. Over time, using many plant species, set ups, various equipment etc, you get a better feel for this. It's not something you go out and do once and that's it.
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When replying, please edit your Subject line so it is more specific
than "Re: Contents of Aquatic-Plants digest..."
1. Micron filtration and nutrients (Sean Kettle)
2. Re: Micron filtration and nutrients (Andrew McLeod)
3. Re: Chemists: Aluminum and the Freshwater Aquarium? (Tom Wood)
4. Re: Re: Chemists: Aluminum and the Freshwater Aquarium?
5. Minimum Light Threshold..... (Rex Grigg)
Date: Wed, 29 Sep 2004 14:02:01 -0400
From: Sean Kettle
Subject: [APD] Micron filtration and nutrients
To: "'aquatic plants digest'"
I have a HOT Magnum that I like to put on the tank once a week to polish the
Which elements, if any, will be stripped from the water column from a micron
filter. I believe Marineland says the filter is good for particles down to
Would any of the macro nutrients be removed? What about traces?
Just curious... Otherwise I'd run the micron all the time as a secondary for
some additional movement in my 75 gallon.
Date: Wed, 29 Sep 2004 19:48:12 +0100
From: "Andrew McLeod"
Subject: Re: [APD] Micron filtration and nutrients
To: "aquatic plants digest"
On Wed, 29 Sep 2004 14:02:01 -0400, Sean Kettle
> I have a HOT Magnum that I like to put on the tank once a week to polish
> Which elements, if any, will be stripped from the water column from a
> filter. I believe Marineland says the filter is good for particles down
> 4 microns.
> Would any of the macro nutrients be removed? What about traces?
> Just curious... Otherwise I'd run the micron all the time as a secondary
> some additional movement in my 75 gallon.
Atoms are way, way, way, way smaller than 4 microns. If your filter could
get anything like the size of elements, it would be filtering out the
water molecules as well... i.e. it wouldn't let the water through (this
technique is regularly exploited in many household objects, such as
kettles, saucepans and cups!)
Most of the macro nutrient, such as NO3, PO4, CO2 etc are simple, small
molecules, and are (at a very rough guess) at least 10,000 times smaller
than 4 microns?
It's not going to remove anything that is dissolved.
thefish at theabyssalplain_freeserve.co.uk
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Date: Thu, 30 Sep 2004 08:45:10 -0500
From: "Tom Wood"
Subject: [APD] Re: Chemists: Aluminum and the Freshwater Aquarium?
"I haven't tried a circulating setup, but I have had a piece of aluminum
wire in several of my tanks for over 5 years and it shows no signs of
corrosion (I used it as a cucumber-kabob for some fish). I would imagine you
will get many, many years out of an aluminum radiator." - Bill
Thanks Bill, long term exposure was my concern since the radiator will be
right over my main electrical distribution center to the tank. A leak would
be more entertaining than I want.
Russell - I looked at the Iceprobe but for my setup it requires drilling the
tank. I also looked at the Peltier (Thermo-electric) industry in general and
there are a lot of products out there that could be adapted. I still prefer
the radiator setup since it requires less electricity to run it.
Date: Thu, 30 Sep 2004 08:06:02 -0700 (PDT)
From: "S. Hieber"
Subject: Re: [APD] Re: Chemists: Aluminum and the Freshwater Aquarium?
To: aquatic plants digest
A power (hang on) filter filter can work instead of
drilling the tank. Set the Iceprobe into that and the
filter pump will recirculate the water.
I think you'll find that peltier devices generally will
cost more to purchase and more to operate than conventional
(compressor) types of chillers. The only rub is if you want
a very small chiller. The main advantage of peltier devices
is that that can be had in very small packages -- small
enough to cool PC CPUs.
The radiator leaking over the electricals shouldn't be a
big deal, at least as far as sparks go -- the GFCI should
trip immediately ;-)
--- Tom Wood wrote:
> Thanks Bill, long term exposure was my concern since the
> radiator will be
> right over my main electrical distribution center to the
> tank. A leak would
> be more entertaining than I want.
> Russell - I looked at the Iceprobe but for my setup it
> requires drilling the
> tank. I also looked at the Peltier (Thermo-electric)
> industry in general and
> there are a lot of products out there that could be
> adapted. I still prefer
> the radiator setup since it requires less electricity to
> run it.
> Aquatic-Plants mailing list
> Aquatic-Plants at actwin_com
Still some time left to get the 65% discount hotel rate.
The Annual AGA Convention, 2004, November 12-14.
aquatic-gardeners.org & gwapa.org
Speakers, 3 Focus Groups in two sessions each, plus Field Trip, Banquet, auctions of equipment and plants from some of the best companies, gardeners & nurseries in the hobby.
Date: Thu, 30 Sep 2004 08:15:21 -0700
From: Rex Grigg
Subject: [APD] Minimum Light Threshold.....
To: Aquatic-Plants at actwin_com
In the web forums I participate in the discussion has come up many times
about how much light you need on a certain size tank to grow plants. Many
times the tank in question is a 10 gallon tank. People have 20-30 watts of
light and are having problems with plant growth and go on to refer to the
watt per gallon rule, which while being a lousy rule does work for most
tanks but not larger or smaller tanks. I feel this is due to a little
explored or understood "Minimum Light Threshold", the idea behind this is
that every plant requires a certain amount of light energy that is not
clearly defined in the watt per gallon rule. Extreme example: We mostly
agree that 4 wpg on a larger tank is a lot of light. But if you take a
gallon of water and a 4 watt light you can't grow plants. Why not? You
have 4 wpg. True, but you have not met the MLT for the plants. I see it
all the time in my terrestrial garden. There are plants that do well in
deep shade and others that require full sun. Light is a nutrient. Some
plants require more of some nutrients that others. And all plants need a
certain amount of light energy to function. This amount varies from plant
So now, please tell me either I'm totally nuts and should put the closely
fitted canvas jacket with the long arms back on or maybe I'm actually on to
In Heaven We were formed...
In Hell We were trained..
On Earth We were released...
United States Marine Corps
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