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Discussion Starter · #1 · (Edited)
Since the watts per gallon rule seems be somewhat inaccurate in today's market of Compact Fluorescent (CF) Lighting, T5HO bulbs, Metal Halides, etc. Can we devise another way to tabulate the minimal threshold of lighting for a planted aquarium with the capabilities to grow most stem, keep a foreground of Glossostigma elatinoides low, and meet the demands of other light requiring plants?

Maybe it would be easier to say from experience what it takes to grow most light requiring stem plants, and then devise a general average for each type of tank. Assuming photo period is 8-10 hours, regular fertilization and CO2 supplementation. Below is what I gather.




Let's come up with a general guideline through calculation and/or observation experience.
Please list you tank's minimal lighting threshold to meet the needs of most stem and light require plants.

- John N.
 

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I think this is an awesome idea John, it could help clear up the confusion about the WPG rule. Maybe we can eventually define medium and low lighting for the thank sizes too.

I'll have to say that 75gallon tanks should do well with 220-260watts CF but I can't completely back that up because I dont have pressurized CO2 yet, glosso is growing horizontal though with 260watts and my current DIY Co2. :D
 

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I use 110 watts of AHS light on a 45 gallon tank. I successfully grow and get good color in Ludwigia sp. Guinea (high light plant), Hemigraphis traian (high light plant), Blyxa japonica (medium light plant) and Alternatheria reinickii (medium light plant). So, my experience suggests that the lighting needs for a 40 gallon tank are less than you listed.
 

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I like that idea too.

But we must include the height of the tank, not just the volume.

Back in 1982 I had a 10 gal tank that was only 10 inches tall. With 50 watts of incandescent light, inert gravel full of mulm, and no CO2 I could grow about 15 species of plants. I believe it was the height of the tank that made that possible.

--Nikolay
 

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I second Hoppy's feelings regarding 40g tanks. I use about 180 watts of spiral compact flourescents with virtually no reflector over my 46g tank. Real CF's with actual reflectors work certainly much better. Still, I get excellent growth in R. vietnam, Blyxa. japonica, HC, and L. 'cuba'.
 

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Discussion Starter · #7 ·
It's hard to separate the two, and I think growing glosso horizontally indicates that most stem plants will grow perfectly fine. But you're right, it doesn't necessarly indicate that if all stem plants grow fine then glosso will grow horizontial.

I think the criteria for minimal lighting to grow "most stem plants" is define by the lighting required to get the best coloration and growth out of your stem plants i.e. Hottonia palustris, Ludwigia sp. 'Guinea', Blyxa japonica,
Limnophila aromatica, Alternanthera reineckii,
etc. If the stated wattage also grows Glossostigma elatinoides horizontally then that's an extra bonus.

Hopefully, we as we grow through this process we can define low, medium, and high light aquariums a little better, and also narrow our definition above.

-John N.
 

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It's a common mistake to look at a "snapshot" of a planted tank.

For example people will suggest certain concentration of fertilizers (say 5-10 ppm N and 0.25-0.5 ppm P). But these are concentrations for a well established tank. Also when the plants grow you may need to increase the N or the P, or both.

Amano's liquid fertilizing "system" is based on the tank "phases". Simply put fertilization is not the same starting with Day 1.

Same goes for lighting. And only a couple of years ago Amano started to use daily "phases" for the light too (about 4 hours of low light, 2-4 hours of very intensive light, about 4 hours of low light).

If we want a practical and useful info on lighting we must point out at least 2 more things:

1. Duration of the lighting period (photoperiod)
2. Intensity of the light

Such pointers will save many issues in the most critical phase of the tank development - the first few weeks. Mike Senske once told us that really it's better to start a tank from scratch then to battle algae once they are developed. The first few weeks are critical in all that.

Here are my views:
Aproach 1:
I would start a tank with only 2 to 4 hours of 100% light intensity for the first 4 to 8 weeks. Preferably around the middle of the day. Of course - never have intense light when the plants have their leaves closed. 2 hours of good light is insanely small period and it needs to be adjusted quickly if some light loving plants are suffering.

The rest of the day the tank gets only ambient light or has very low to low light (0.5 - 1 wpg for a total of about 8 - 10 hours a day). After this initial period of up to 8 weeks the tank can be lit for 11 or even 12 hours with 100% intensity of the light.

Aproach 2:
For the first 4 to 8 weeks have the lights on for 8 to 10 hours a day but using only 50% of the light suggested in John's list.

To me that approach is inferior to the first one but it could be an alternative. Still - plants do prefer intense light (although for a short time) than low light for a prolonged period.

Both approaches have one goal - limiting the algae in the first few weeks of the tank life. What I've seen is that sometimes the algae seem to have an abrupt "breakdown" - they seem to "give up" trying to establish themselves in that tank.

Controlled light really messes algae up :D. It may not preven them 100% but it keeps them "weak". After several weeks of such weakened state I've seen them completely disappear from a tank, literally in 1 day. From that point on the tank is very, very stable and beyond clean. I have 2 such tanks here at home that have undergone that kind of development and I abuse them badly (irregular maintenance). The only problem is starved plants and slow growth but never algae.

--Nikolay
 

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Controlled light really messes algae up :D. It may not preven them 100% but it keeps them "weak". After several weeks of such weakened state I've seen them completely disappear from a tank, literally in 1 day. From that point on the tank is very, very stable and beyond clean. I have 2 such tanks here at home that have undergone that kind of development and I abuse them badly (irregular maintenance). The only problem is starved plants and slow growth but never algae.
--Nikolay
I've seen this too. This is perhaps a bit off of John's topic, and deserves its own thread, but it's almost as if some signal tells them to pack up shop and leave town. It's a very intriguing phenomenon.
 

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i have 96w over my 20H and everything seems to be growing great!

i dont have hc but i do have hm that grows low to the ground and all over the foreground actually. dose seachem's line of ferts per their rec. chart and ~30ppm of co2 i plan on switching to GW ferts that i have when the seachem stuff is gone and i have switched to pressurized already.



i had the HM growing all over the front and covering the downoi but i have since cut all the HM from the downoi area to the diffuser out for another tank.

also to add i have a 2.5g with 18w coralife pc over it and it grows riccia and HM low to the ground as well and that tank has no co2 or ferts just flora base and weekly w/c's
 

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Discussion Starter · #11 ·
Great points Niko. It is hard to take a snapshot tank and say that's how it's going to work for everyone at all points in time. Definately ideas to be considered.

Eklikewhoa, with 96 watts over your 20 H gallon tank how long is your photo period and what fixture(s) and reflectors are you using to the 96 watts? Beautiful tank by the way too! ;)

-John N.
 

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Oops, new I forgot something.

96w 6700k quad bulb coralife fixture on coralife legs
Open top tank
Photoperiod of 8hrs

Thanks for the comment john!
 

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A couple data points.

I have an "insane" light level tank using 4 of the 6 bulbs of a 48 inch Tek Light fixture over a 55 gallon tank. It's 4 watts/gallon, but with the reflector it's equivilant to more than 6 watts/gallon from lamps with lesser reflectors.

It's a new tank, in that it's not stable yet, so I can't give good figures. Also have some algae bothering some plants I picked up a store that were contaminated with it. Need to put some fish in the tank to see if they will clean it up for me.

Just some very amusing observations for now:

Java fern adapts better to this high light than Bacopa carolina, Egeria densa and Mayaca. But the Potamageton gayi really likes it that bright. (The others had a burnt look to their leaves.) I may also just not be giving them enough nutrients for all the light they are getting.

Above it, I have two 20H's side by side with a 40 watt Grow Lux and 32 watt Octatron 6500K. Does really well for the anubias/crypt propagation tank and the low-maintenance medium light tank with misc plants.

As far as coming up with an index, I'll rephrase what I read on a posting saved at the crypt:

* Get a light meter that measures in lux and put over it a photographic filter that notches out green and gets rid of all infrared. (Is there a photographer in the house?!?) This would give us a good number that multiple people could do. Put the thing inside an empty aquarium and make measurements with different lights. (Somehow enclose the thing and make measurements in one filled with water.) This would not perfect, but this would be a much better estimate than what we have now.
 

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Here's where I originally saw the photographic filter over a light meter idea, it's from 1998:

Units of PAR

For final measurements and to compare results, as George suggests, I plan to
use a filter over a standard cell (as found in a Lux meter) that is designed
to allow photography in a fluorescent-lighted room with daylight film. That
pinkish/purple filter will give comparison numbers a bit more meaningful for
plant growth, I think.

For that, lux sucks, as does lumens. PAR is actually only somewhat better.
My filter will basically measure relative PAR with a lux meter, even with
different lamp spectra, by de-emphasizing the green part, which most plants
reflect away, anyway.

Wright

Wright Huntley, Fremont CA, USA, 510 612-1467
 

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Hello (my first post)!

My tank is 80 gallon, 20" tall, 10 h lighting period and 136 W T8 + reflectors.

I grow glosso fast and absolutely horizontally.

How's this correlating with the figures in the first post, I wonder.

.Nixe
 

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lighting

I have a 125 gal discus tank with 440 watts of cf on top, I use diy co2 reactors and diffusers, and I have grown glossostigma in my tank very well, It just about all died from an algae bloom, that was when I first started, as far as anything else, you name it and I can grow it I am sure of this.
 

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Re: The Rules of Lighting for Planted Aquariums

uhhhh the only thing i am gathering so far is "buy as many watts as you can possibly afford"

:-\

am i wrong on that?
 

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Re: The Rules of Lighting for Planted Aquariums

uhhhh the only thing i am gathering so far is "buy as many watts as you can possibly afford"

:-\

am i wrong on that?
I would answer yes. :)

While very high lighting (ie 4wpg+) is certainly doable, IMO it requires a certain level of experience and is definitely not an absolute requirement for a successful healthy plant tank.

You can grow pretty much anything with 2.5-3.5wpg of good lighting.

My comments relate to tanks larger than say 40l (10g). For smaller tanks more wpg is required.
 

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I would've lowered the minimum level in the last post. I get very good and colourful growth under 1.8WPG using T5 HO lights. Maybe the WPG (that has already been said is not so much use anymore) is for T8s and that 1.8WPG = more in comparison to both PC and T8 (although PC seems to give more intense light instead of spread light)

Much better than when I had 2.5WPG of compact flourescents!!!!

In fact I would often have centre of the tank staghorn growing on the plants directly underneath the CF lights whereas now I think the better spread of light from the HOT5 seems to be better as this phenomenon has disappeared (it never appeared when I used T8s only when I used PCs!!!!)

Andy
 

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Wow if that is the ruling... my tank is waaay too bright then.... 20gal 55w?? Mine is 107 Watts mind you :) lol
 
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