Updating the WPG rule (theory)

[Wizzard~Of~Ozz]

czcz, I find your response most interesting, Yes I assume 100% reflectivity, it's not so much a question of that, since a CF with 95% reflectivity vs an NO with 95% reflectivity have the same variation.

Ahh yes, the "no change in output" by switching the 50/50 for a flora bulb. the flora bulb has an output around 14-1500 lumens. the 50/50 has an output of 14-1500 on the 10k side, the rest is actinic. but you are correct in assuming the NO3 is responsible..

Anyway, let's test. My high-light 8gal has 2x13W CF and 1x20w NO. I came to using this light by trial and error through obervation of high light plants. (There is also light from a 23w spiral screw-in CFl on the side for a nano, but I am ignoring it.)
Using your calcs above for equivalent NO WPG
(26w CF * 1.75w NO equivalent/(w CF)) + 20w NO = 65.5w equivalent NO

The fitchfamily.com derived Amano calc gives 59w. Pretty close.

That is great to see that they are that close in agreement..

For the T8/T12 comparison I used 2 phosphoretically (is that a word?) identical bulbs, Philips daylight deluxe, I have T8 and T12 for the bulb. Assuming identical phosphors are being compared, this difference would remain true for any bulb out there.. (I'll confirm with another set of bulbs)

Perhaps the best way to start a rating would be lumens per gallon.. but since some manufacturers don't make this information available, it would make it difficult.

Quote:

I've noticed more and more people are using Watts from a CF to equal 1WPG..

A watt is still a watt though, and so WPG is the same. Of course your point is with relative light output, and so you should move forward in posts off-thread with "lumens per gallon," or perhaps "relative/equivalent NO WPG" or something.

You are right, a watt is a watt, I'm trying to say, a watt of light energy doesn't necessarily equal a watt of light energy when different bulbs are in play.

I am of still of the opinion that WPG's usefullness ends whereever CO2 is necessary, and the rest is tweaking to get past the threshold of high light, if wanted. I suspect that a full analysis of lighting and all its variables -- very small and high volume breaking the rule, tank surface area, height, reflector quality, glass tops, and so on -- makes a one-size-fit-all standard unlikely. Instead, it is better to tackle light with experience and trial and error, as most tackle stocking,

I'm not trying to make a 100% fool proof system, but I think +/- 5-10% is far more accurate then the current +/- 75% or more. I also know using all variables is near impossible, but to rank the limitations would make more sense, the minor ones must be left out or risk making it to complicated to calculate.. Assuming most things can be set up in a table, it would make things much easier to

I will read a couple more of the links posted.. they look interesting.

Another problem, Hagen chose to market their bulbs on a "lux" scale, well 180 lux = 180 lumens. According to measured results, the lumens of a power glo bulb is 2200.. Interesting those chose to make their own scale..

Conversion 1 lux = 1 lumen/square meter..

As for the link on light threshold.. I follow every thing but the last portion. he has the right idea tho, surface area is most important, something that even I overlooked when I got stuck on the "per gallon" guideline..

This is proving to be very interesting, so far I've broken it down to lumens / Sq. inch, initial loss, depth loss.. But there are still some hurdles to overcome.. like what is "high light" "very high light" etc.

I've based the levels on
220w NO T12 on a 55Gal - Very High Light (formerly 4WPG)
165w NO T12 on a 55Gal - High light (formerly 3WPG)
110w NO T12 on a 55Gal - Moderate Light (formerly 2WPG)
055w NO T12 on a 55Gal - Low Light(formerly 1WPG)

I think this is fairly correct. 220W on a 55 is a lot of light to grow anything..

agree?

 

[czcz]

Yes I assume 100% reflectivity, it's not so much a question of that, since a CF with 95% reflectivity vs an NO with 95% reflectivity have the same variation.

I am thinking more in terms of reflectors for certain bulb shape and such. AHSupply notes that their reflector limits light lost from restrike from U-tube type bulbs, for example. It may be marketing of course, but I think eliminating the reflector/restrike/etc variable with a blurb stating 100% efficiency is assumed will only make the article more sound.

Perhaps the best way to start a rating would be lumens per gallon.. but since some manufacturers don't make this information available, it would make it difficult.

I'm not trying to make a 100% fool proof system, but I think +/- 5-10% is far more accurate then the current +/- 75% or more.

I think sourcing the aquabotanic article, along with the Phillips white papers, for an average "lumens/watt lighting type" will help here, and of course will make at least 2 sig figs reasonable for NO WPG equivalents. I've started with CF but have to stop because I am supposed to go somewhere , but am close to 85 lumens/watt at the moment. I will post it later (likely tomorrow) along with T12 and T8 if you do not do it first. (Even if you choose to not use the data I do not mind, as it will satisfy my curiosity.)

I also know using all variables is near impossible, but to rank the limitations would make more sense, the minor ones must be left out or risk making it to complicated to calculate.. Assuming most things can be set up in a table, it would make things much easier to

This is proving to be very interesting, so far I've broken it down to lumens / Sq. inch, initial loss, depth loss.. But there are still some hurdles to overcome.. like what is "high light" "very high light" etc.

What do you think about a survey of AA for possible important measurables (watts, volume, surface area, tank heaight, etc), so we can play with the numbers and run comparisons with different invented metrics later?

I think this is fairly correct. 220W on a 55 is a lot of light to grow anything..

agree?

Absolutely.

This is going to be sweet Up for helping if you want it.
Joe

 

[azn_fishy55]

So I really have 5.6 watts per a gallon of cp over my 30 gallon.Thats lots,thanks good ness I started getting my nutrient levels in line,maybe my green water will go away.

 

[Wizzard~Of~Ozz]

Ok, the write up is getting really long (at 9,000 or so letters), fingers are getting sore, but I will pres on. czcz, thank you for your offer, if you can compile the information (perhaps a 5000k, 6500k and 10000k average could be handy?) I will certainly use it. Thanks for your help. Oh, and I have solved the WPG on large and small tanks problem.

 

[gfink]

Here is something I was working on a few months back. I created a spreadsheet that allowed you to input the power (Watts) of any bulb, and the output of visible light (Lumens). You then input your "Illuminence Goal" in Lumen/in^2. The spreadsheet would then calculate this for all standard size tanks. The attached graph illustrates why the WPG rule doesn't work for small and very large tanks. The simple explaination for this is that the volume and area don't increase at the same rate through the tank sizes. The ratio does not increase linearly like the WPG rule does.

I can't attach the spreadsheet, but I will e-mail to somebody if they want to see it. But, note how the graph shows how small and large tanks don't follow the WPG rule exactly. (even though this graph is for one set of bulbs)

 

[BlazerFRS]

Oh, and I have solved the WPG on large and small tanks problem.

He drops so innocently....

I'm VERY curious.

You are right, a watt is a watt, I'm trying to say, a watt of light energy doesn't necessarily equal a watt of light energy when different bulbs are in play.

I think what you mean to say is that a Watt of electrical energy consumed by a bulb is not ever equivalent to a watt of light energy output from the bulb... nor is it always equivalent to constent a number of lumens light output across different bulb systems. Efficiency varies with different bulbs. You've certainly covered that ground, but I just felt like pointing this out as clearly as possible to those who may not understand.

Very good discussion so far-hopefully a better lighting standard will come of it!

 

[Wizzard~Of~Ozz]

That is a very good spread sheet gfink, it looks almost exactly on par with what I've found.

Well, with no proof reading yet, this is what I've come up with, it will update as I save it.
If you notice some wierd comment, that's just me talking to myself and may not be in the final draft.. sometimes results do shock me. (and I am designing some formulas that can put out some odd numbers)

 

[BlazerFRS]

Lookin good so far!

Very good points

 

[Wizzard~Of~Ozz]

I'm finding mixed results. the effect due to absorbtion in the water is incredible.. to the point of 12.5-25% loss every 4", so the numbers I posted are based on 18" depth.. if you change it to 10" the lighting is virtually 1/3rd of the calculated value.. I'm still researching.. but the base arguement I made at the beginning of this thread is very clear.. but the WPG (based on T12) is proving very persistent with only a few differences noted at certain tank sizes.. some higher, some lower.

After reading, the absorption rate in freshwater results in less reds getting through, blue only suffers 60% of reds. The plants can adapt to strong blues and mild reds, so increasing or decreasing the lights is only really necessary at extreme depths (over 24").. finding it difficult to get an answer without having to learn quantum physics. but the best answer I found is to keep your water clear

 

[czcz]

Ozz,

Ivo Busko's data on aquabotanic separated by bulb type and with lumens/watt.

T12
bulb         watts lumens lumens/watt
Aquarelle       38  2380  62.6
TLD950          36  2350  65.3
GE SPX65*       40  3050  76.3
Triton          40  2200  55.0
Daylight Dlx    40  2550  63.8
GE Fresh & Salt 40  2350  58.8
CoolWhite*      40  3050  76.3
VitaLite        40  2340  58.5
Gro-Lux*        40  1200  30.0
Warm White*     40  3100  77.5
Cool White Dlx  40  2200  55.0
Perfecto*       40  1500  37.5
C50             40  2250  56.3
Osram Biolux    40  2400  60.0
P&A             40  1900  47.5
AgroLite       115  7500  65.2
GE Freshwater*  40  1475  36.9

(some of the above may be T8 or T10, and was not specified by Busko in the article)

avg 57.0 lumens/watt

After quick and dirty removal of all bulbs with greater than 20% deviation from the mean (marked with an asterisk above)

avg 58.9 lumens/watt. Lets call this 1wpg of NO moving forward in this post.

Compact flourescent
Dulux54    55  4800  87.3
PC6700     96  8100  84.4
PLL950     55  3800  69.1
PC6700     55  4230  76.9
Ott CF*    23  1200  52.2

avg 73.98 lumens/watt

After removal of all bulbs with > +/-20% deviation from the mean

avg 79.4 lumens/watt

Known T8
ADV850  32  3100  96.9
T8/741  32  2850  89.0
TL950   32  2000  62.5

avg 82.8 lumens/watt

If we remove the TL950

avg 93.0 lumens/watt

Known T10
PowerGlo   40  2200  55.0
SunGlo     40  3100  77.5
AquaGlo    40   960  24.0 
FloraGlo   40  2180  54.5

(T-10 from Hagen's site)

avg 52.8 lumens/watt

Removing the AquaGlo

avg 62.3 lumens/watt

So, if we interpret this back to "equivalent watts to T12 NO" by using lumens,

1w CF = 1.3W T12 NO
1w T8 = 1.6w T12 NO
1w T10 = 1.1w T12 NO

I believe this approximation, especially the first, is sound considering sample size and quick and dirty deviation. I can do standard deviation with larger samples if wanted. Interesting that T8 comes first in this analysis, as well as Busko's PAReff metric! Makes me one to get off my behind and do ODNO with T8

Using this conversion also gets 54w equivalent T12 NO for my 8gal, if usefull for comparison to fitchfamily.com analysis above.

re: article

Very nice! Love the growing site, too. I did not discover the wpg vs small and large tanks, and so do not need credit. Perhaps Rex Grigg should get mention as he was one of the first (if not the first) to spread the idea around about surface area, quantifying the large/small tanks breaking WPG thing.

The T8 bulb, while it consumes less power actually outputs more light per watt.

My F18T8 Glo bulbs are still 15w. Do you happen to know if the lower wattage consumption thing is for bulbs longer than 18"?

You have a 10Gal tank, you want to hit Very high light. That would require 19.09 lumens / Sq. inch, there are 200 sq inches in a 10 gal (20x10) so 19.09 x 200 = 3818 Lumens or 76 watts of T12 NO light (3818 / 50 Lumens/watt) or, if you are going the T8 route. (3818/87.5 Lumens/watt) = 43.6 watts of T8 lighting.

You may find it interesting that with the numbers above, it is 65w T12, 61w T10, 41w T8, and 48w CF. The T12 mark hits the fitchfamily.com analysis almost perfectly.

gfink, interesting graph! Did you use standard tank sizes for in^2 for given volume? Just curious.

Joe

 

[Wizzard~Of~Ozz]

I'll update the numbers when I get back from work. I didn't mention T10 since it only seems to be used by Hagen. Also the powerglo T10 is 40w which seems to drop it's efficiency to that of a T12.

Great work sorting the data.

 

[czcz]

gfink, sorry, reread your post. Very cool.

 

[Wizzard~Of~Ozz]

czcz, any thoughts on the effect of the short height on a 10Gal? I know what the lumens/"^2 is. but with the lack of loss from having to penetrate the depth of water the wattage can be effectively cut in half. (best answer I can find is 2300 lumens lost @ 8", over 5000 lost @ 16" , based on 16000 lumens input).. I would have figured a difference that high I would be able to see in my tank (light fading as it approches the bottom)

 

[Wizzard~Of~Ozz]

added to first post.
Well, on my "crusade" (I find that humourous) I've finished most of the typing.. hopefully it shows the major differences and can help some people.

I will need some people to check the information, if you se anything that you disagree with, I appreciate the feedback.

Here is the page so far

 

[rich311k]

I meant that it a good way. I think you are doing great research and your article is very good and quite informative.

If my algebra is correct and please correct me if I am wrong:

Your lighting level = watts of bulb (or bulbs) X lumens per watt / surface area.

 

[Purrbox]

This thread is very interesting, and I've enjoyed following it so far.

I applied your formula to both of my tanks. For my 5 Gal Hex (it was a bit of a bear trying to figure out the surface area for a Hex!) it appears to be dead on with amount of light and the light level. With 10 Watts over the tank it definately acts like a Medium - Low Light tank, and 10 Watts was right between Low and Medium Light. However I think it may be off for my 2.5 Gal, as gives a range of about 12 - 15 Watts for High to Very High light. I've actually got 26 Watts over the tank and while it is definately a High Light tank, I'm not sure that it qualifies as Very High Light let alone well over Very High Light.

One nit picky thing, you might want to go over you Caps in the article as there were several sentances that the first word wasn't capitalized. Other than that, very readable.

Great work so far!

 

[Wizzard~Of~Ozz]

The measurements I have for a 2.5Gal is 12x6, thsi is 72Sq" x 19.1 (very high) = 1375Lumens / 50 lumens/watt = 27.5Watts of T12 lighting.

I see the error, I calculated the lumens/watt in the ratings to 50Lumens/watt, but when you reverse them it's 58.. I'll adjust it. (done, I adjusted the latter half, but didn't adjust the base unit, it now works out to 27.4watts)

thanks for the heads up about the Caps. I usually end up letting go of the shift key before I press the letter typical of me typing fast.

 

[Purrbox]

The actual measurements for my 2.5 Gal are 12 x 5.5 and I'm working with CF lighting. With that I'm getting 14 Watts for High Light and 19 Watts for Very High Light. Even with the stock measurements of 12 x 6 it's 15 Watts for High Light and 20 Watts for Very High. Definately closer than it was. Probably some of the remaining difference comes with the height of the lights over the tank and that I'm using a glass cover. Any remaining difference is probably due to the actual bulbs that I'm using, since they're just generic 6500K that came with the worklights.

Remeasured the 2.5 Gal for the poll thread that was started to gather data for these calculations, and discovered that I'd mismeasured the tank. It's actually 12 x 6. Must not measure in the Dark!

 

[czcz]

(article is timing out)

I have no good thoughts on the height thing, as my tallest tanks are 12". I think it is not a big deal assuming no obstruction of light though, since lighting level recommendations form say, carpeting plants are with applied tanks and height in mind, and so loss of light from water is basically built-in. Riccia is considered a high light plant when used as a carpet, but will grow in much less light when left floating, for example.

Assuming you are thinking of using, say, a 55gal's height as baseline, I think reducing the amount of light needed for, say, a 10gal based on light penetration would hurt things. On a very short tank, the in-progress formula results are pretty close to applied high light tanks, for example. When you come up with a metric for it we should certainly see what comes of the numbers, though. I will start that survey mentioned earlier.

 

[Hara]

so where do T5 HO bulbs come into play? ie: 3ft long twin tubes at 39 watts each? Do they get calculated the same as T5 NO blulbs do? ( I am not good at this stuff, so have patience please)