Updating the WPG rule (theory)

[czcz]

These three sites (first on Google) list T5 at ~104 lumens/watt and T5HO at ~92.6 lumens/watt

http://www.4hydroponics.com/order/bulbs.asp
http://www.uppco.com/business/LI_05.asp
http://www.ecmweb.com/ops/electric_fluorescent_lamp_coming/

T5HO lumens/watt matches up to "Pentron41 HO" in Busko's AquaBotanic article. Interestingly, this is effectively the same as T8 above.

1w T5HO = 1.6w T12
1w T5 = 1.8w T12

(with a 48" bulb, T5 is 28w, T8 is 32w, T12 is 40w, and T5HO is 54w.)

Here is MH since Busko's article has 3 samples all well within 20% of the mean.

Metal Halide
MHN         150   11250  75.0
Iwasaki65   150   12000  80.0
MH          250   23000  92.0

avg 84.1 kumens/watt

1w MH = 1.4w T12

(edited for formating)

 

[CGGorman]

I checked my Amano books. They don't specify lighting type. Just wattage and number of lamps. He seems to run a lot of wattage, so I'm guessing NO...

 

[Purrbox]

I don't think this has been suggested yet, but once you get the formulas all hammered out it would be really awesome to put together a little web interface (something along the lines of Chuck's Plant Calculator) that would allow you to enter some info and have it spit out the lighting levels.

Something along the lines of a selector for Aquarium shape (rectangle, hex, etc) with dimensions input appropriate for the size, and then lighting type, and it spits out the lighting levels. Or you could reverse it and enter the amount/type of lighting that you have over the tank (Aquarium shape with dimensions) and it would tell you where your lighting falls.

 

[Wizzard~Of~Ozz]

Sorry guys, pulled the wrong cord yesterday and spent the evening fixing the server Guess it's better to leave well enough alone.

Purrbox, I do program in PHP (web scripting language) so that would be no problem

I think MH is in a class of it's own. The article adresses Fluorescents, HID bulbs are a bit different in a couple of aspects.

T5 = CF they are the same bulb AFAIK.

 

[czcz]

re article: FWIW, on the 10gal example calc, I think you should either use the raw average for the one with quick and dirty deviation for both T12 and T8, not one of each. The TL950 has 24.5% deviation from the mean, so it's not based on being the lowest. (Same with all calcs thus far, btw.) How about we just replace that sample with your numbers from Phillips?

T8
ADV850   32  3100  96.9
T8/741   32  2850  89.0 
Phillips 32  2800  87.5

avg 91.1 lumens/watt

1.5w T8 = 1w T12

(Removing samples greater than 20% from the mean and two sig figs for "equiv NO wpg" are arbitrary choices to make more valid the results from small samples.)

re T5 and CF being the same - I read your quote earlier, and please forgive my ignorance, but I need more of an explanation. A very informative site separates them into two articles -- CF, T5 under Flourescent -- and has this quote, which seems to indicate they are different.

One manufacturer sells fixtures with conical reflectors that closely imitate the look of a typical metal halide fixture (Figure 1). However, the compact size of these fixtures limits them to the use of shorter compact fluorescent lamps, which are less efficient and have a shorter life than long twin-tube and linear T5 lamps.

BC Hydro - HID Versus Fluorescent for High-Bay Lighting
(Worth researching more in regards to life span section of your article. I think this plus lumens/watts makes T5 a better bulb than CF, but I sure wish T5 bulbs were more commonly available.)

If they are the same, would it not invalidate lumens/watts, since they are not the same for CF and T5?

 

[Wizzard~Of~Ozz]

I will add the results from the information given by Philips when it get's here. I've updated the description for why the outer numbers were removed.

HID output more in the UV band, this makes them more suited for plants AFAIK. tho I haven't seen the spectral outputs. Also tri-phosphor fluorescents output in "spikes" whereas HID as I know it are a smooth band..

The Lumens/watt according to GE.

Typical lamp efficacies:
Edison’s first lamp ......................................................................... 1.4 lpW
Incandescent lamps .......................................................................... 10-40
Halogen incandescent lamps .................................................................. 20-45
Fluorescent lamps ........................................................................... 35-105
Mercury lamps ............................................................................... 50-60
Metal halide lamps .......................................................................... 60-120
High-pressure sodium lamps .................................................................. 60-140

http://www.gelighting.com/na/busine...alogs/lamp_catalog/downloads/cat_appendix.pdf

The reason I say MH bulbs are a different class is they are arc based. this allows them to output a spectral characteristic closer to the sun in respect to less spikes. the base bulb outputs broad spectrum, the peaks are there typically for colour intensity. This is what I've read on them.

 

[czcz]

Nice resource, thanks.

I should have done a better job of quoting in context above re T5 and CF. The fixture they are describing is not MH, but one that uses CF and resembles MH. In the article it can be seen under "High-intensity fluorescent fixture designs":

Figure 1: Fluorescent or HID?

This fixture uses eight 42-watt compact fluorescent lamps and is designed to resemble a typical HID fixture.

 

[PrettyFishies]

So what would the wpg be for a 29 gal with 65W of PC light?

 

[czcz]

Equivalent T12 wpg for 65w CF/PC is

65w CF * 1.3w equiv T12/w CF = 84.5w equiv T12
84.5w equiv T12/29gal = 2.9wpg

If you wanted to apply Ozz's article, take the formula nicely rearranged by Rich and reference Ozz's chart for lumens/sq in for lighting level:

Your lighting level = watts of bulb (or bulbs) X lumens per watt / surface area.
(65w CF * 79.4 lumens/watt CF) / (30"x12") = 14.3 lumens/sq in

This would put you in moderate-high lighting according to Ozz's article so far. One could make a case that you are much closer (or at) high light. In your experience, is your tank closer to medium or high light?

 

[PrettyFishies]

Don't know... Haven't setup the tank yet Just trying to get info... Don't want to plan for the wrong equipment....

 

[czcz]

Cool, lets play with it a little then. In terms of lumens/sq in, your intended set-up's closest match so far in the survey CGGorman's 70gal, who if I remember correctly, is getting to the point of utilizing ferts and CO2 to meet all plant needs (he has posted a lot about that tank recently). Fwiw, your second closest match was my 8gal when I was running 2x13w CF (13.23 lumens/sq in), and I could get reds from some medium light plants, but battled BBA due to insufficient/fluctuating CO2 (pic). This would seem to indicate that stable and high CO2 and fertiization will be required in your planned set-up, and you will have at least medium-high light. For whatever its worth.

Ozz, what do you think about using 2.75wpg over the 55gal as the high light threshold, and 3.25wpg as very high light? It helps me in the "does the result make sense" test with the survey and some theoretical tanks, and it makes sense that the gap between high and very high light is much smaller than 5 lumens/sq in. Just a thought.

Here is an interim Excel spreadsheet for some quick calcs until you get around to PHP, should you or others find it useful. All formulas call luimens/watt in the bulbs book, including equiv T12 watts calc in that book.

 

[Wizzard~Of~Ozz]

I love how fast it is to make things in Excel. I also program in VB.. hobbies hobbies, where do they end.

I would leave the thresholds for each level up to you, I just went up in standard "WPG" steps.. as for what the plants require. well "moderate" doesn't mean much when you see it on a card.. and I can find no difinitive "this is moderate light" range.

I recommend Co2 for any planted tank, even low light. the plants gain an extra 7% growth per day? (can't remember time frame) but it's compounding..

Is the threshold really that close? The lack of rotala Macranda in my tank would lead me to believe 3.7 is approx the threshold since magenta will grow.. Just my thoughts from my experience.

 

[czcz]

I've not tried to narrow anything down yet and am just picking numbers from the air for those thresholds vs said examples, mostly theoretical. (I think my 8gal at 20.8 lumens/sq in is in very high light, but think about adding more, fwiw.) If there is more data in the survey and experiences/thoughts in your thread I'll try to crunch the numbers, and should be able to offer some anecdotal thoughts after I get ODNO T8 up. Right now I think maybe the 55gal's funny shape screws things up a little. For example,

50gal standard (36x18x19) T12
wpg   lumens  lumens/sq in
1       2945      4.5
2       5890      9.1
3       8883     13.6
4      11780     18.2

 

[Wizzard~Of~Ozz]

I've added an Estimater to the article. The numbers are adjustable.

source code for the calculation is also available if anyone wants to learn a bit of PHP (nothing too advanced in there yet)

 

[BlazerFRS]

Nice calculator; I like
Especailly since it tells me I've got the fixtures laying about to hit high light at my leisure...

Good work so far! All your so far results match up exactly with all my limited experience.

 

[Wizzard~Of~Ozz]

Oh, if you need help with ODNO calcs

2x ODNO = 150% output
3x ODNO = 175% output
4x ODNO = 200% output

so if you overdrive 2 bulbs at 2x each it equivilates to 3 bulbs

I used 55 Gal because that is the 1 tank I've heard is very accurate to the WPG rule.. I think some more numbers would be needed..

Glad you like it, figured I'ld just throw out all the numbers there since it doesn't require any real extra time..

 

[czcz]

I've added an Estimater to the article.

Very nice.

--

If you have not already, please post tank stats in the survey for this thread. Thank you.

 

[Jchillin]

Ok, with the established theory, I'm at a robust 1.8wpg instead of the 1.4 under the "old" math. This is extraordinary if the theory holds. Changes the entire thought process of tank needs, especially where CO2 becomes a concern.

Very nice job guys. Where do we go from here? Are we ready to launch the "LPG" methodology in regard to bulbs other than T12's?

 

[Wizzard~Of~Ozz]

I think we would need a concensus, also an understanding that spectrum is equally important.. (you can't use actinic or blacklight and expect it to count)..

I'll try to update the article, the theory is sound IMO. but the problem is, it would be IMO if most don't agree..

We also need to establish what is high light, Very high, mod. and low. The more people that contribute what will and won't grow in their tanks and the respective light they use (color temp and bulb brand are helpful) would make the levels a bit more accurate.

http://www.aquariumadvice.com/viewtopic.php?t=72806 for the survey.

 

[greenmaji]

CGGorman.. I didnt see an answer to this but that is a lux meter (it gives you an idea of how well the light is penitrating the water not so much it's actuall intensity)

I think if T5-HO was added to the list of light output/watt and possible ODNO outfits that diffent light source selections might be made around here..