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So 2.9W/gal for 4x 40 W T12's on a 55 gal tank is still lower light than 40micromols........

So around 3W/gal is considered high light by many that use the conversion, then they run out and apply it to a T5 or a PC light set up and assume they are the same.

I'm not sure why testing is so horrible for lighting when so many on the forums over the years harass people about the need to test things like NO3 or PO4 critically, or Fe and Mg etc......balancing K+ and all sorts of hoodoo.

Then do not measure light.

CO2 has it's many issues, but light is fairly straight forward and not hard if you use a meter. Hoppy's graphs illustrate the point pretty clearly.

Does not matter what differences tank to tank we might have, with a PAR meter, you have a good idea for comparisons. Quick, easy and lightly(pun intended) do not have to do it again from then on. Cost is the main issue for the PAR meter, some have suggested renting, but many are too cheap even for that, but are willing to spend $$$ for test kits.
You can also buy it, use it, rent amongst local folks, then sell it.

Why would you need it much more unless you are like Hoppy or myself interested in doing comparisons in real or hypothetical cases?

Might as well sell it back for 200$ or so.
If you buy it for 200-240 in a group buy, it cost you next to nothing.

Folks will buy them for the 200$ range pretty easily.

Regards,
Tom Barr
 

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This is one reason it's very hard to generalize with PAR or light in general without actually measuring the tank with a light meter.

In otherwords,it's still a guess.

Now if you have the exact same set up, or enough general experience, then you might be able to hit a reasonable target.

You can say something if the light systems, distances, etc are exactly the same. But then it's harder to generalize.

That is the trade off, if you tried to apply this to dosing without measuring anything....you can quickly see you are guessing a lot. You can still eyeball it, but .......that does little good for quantifying or getting a good range etc.

I suggest and still suggest a light meter if you are serious.
Rent, group buy etc........

Then you know.

Why expect others to make some chart and table for you that is better than say the watt/gal rule? No chart is going to save folks here. I think that is what many are thinking and wanting.

I do not think that is realistic.

Nutrients are the easiest thing we can measure, light is the next, CO2 is by far the hardest. All this talk about "each aquarium being unique and it's own ecosystem" blah blah seems tossed out the window when it comes to light and CO2.

You have 3 main things(light/CO2/nutrients), if you apply a standard to one of them, then it should apply fairly to all 3.

Regards,
Tom Barr
 

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The tank is 24 inch high, there's 2 inch of substrate at the front to middle and the lights are 2 inch from the water surface. At the back there's 4 to 5 inch of substrate.

regards,
dutchy
Hummm..........might try and see if the light could be raised about 6-8" above the water's surface.

This seems initially counter intuitive.
But this reduction in intensity is offset by a better, more even spread and less hot spotting.

You have enough light to burn, and can adjust the intensity unlike many in the USA. I'm not sure if the hood you have will allow you to raise the light though.

Regards,
Tom Barr
 

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Hi Tom,

No need to raise the lights. I'm not using 95 micromols, but 55 micromols without reflectors but with a white painted hood, and light can spread around that way.

if I need less, I just turn the knob ;)

regards,
dutchy
I know, that's why I suggested raising it to see the difference in the effect vs changing the intensity, the effect is/should be different.
You might find this more useful than turning the knob.

Regards,
Tom Barr
 

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I just remeasured and adjusted my tank's lighting.

My 120 Gal has about 41" from light to sediment, 1.8W/gal of T5, and the PAR is 30-34 micromols even with wood etc in the way.

My 60 Cube now has 0.8 w/gal and similar PAR, at about 37" distance.

Now.......30-35micromols should grow most plants fairly well.

I strongly urge folks to measure and re evaluate their (too) high intensity lighting and consider using much less, you simply are causing headaches for yourselves and the myth of the need for high light.

Note:
All values are at the sediment and in real tanks with water, wood etc.

Regards,
Tom Barr
 

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The Tek clearly was superior to the Current brand in most all aspects IME.
Higher grade stuff can be directly measured and then justified.

I like the Gieseman bulbs, nice colors and good performance.


Regards,
Tom Barr
 

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They are actually local and will build to suit.
I have not used them for one main reason: the hoods are ugly, and aesthetics are important to me.

Others with a PAR meter might be able to comment.

I test when convenient, I do not go looking for various hoods to measure.
I'd rather good look for hardscape materials, wood, etc........

Regards,
Tom Barr
 

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http://www.ahsupply.com/54wInstalls.htm

For folks with wood type hoods, this 2 bulb configuration is all you might ever need for most tanks up to 75Gal.

Certainly not more.
Ideally, you'd be able to have each bulb on a timer.

Even 1x 54 W on a 55 gallon tank is enough to grow most plants.

I use 2x 24 w at 1 meter distance from the sediment bottom and am getting 30-35 micromols.

20-25 are the lower limits for many species.
40-50 is optimal for most

Regards,
Tom Barr
 

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Who/what decided what counts as "too high", "high", "medium", etc. light in this chart?
It is arbitrary. We need to pick and chose something.
What is the min light you can grow 95% of all plants? 20-35micromols.
That is less arbitrary.

What is the max level of light that will no longer increase growth independent of CO2 and nutrients? About 400-600 micromol, not many will fine this fun however.

If CO2 and nutrients are non limiting, then adding 2-3x more light will increase the rates of growth enormously.

A good ideal light level will minimize and increase the light use efficacy independent of other factor AND........also demonstrate at a very high level of skill for scaping (Horticulture/landscaping design)

This seems to be about 40-50micromoles.
This was done by testing people's aquarium who have placed very high in the contest etc.

Is the objective: to merely keep plants alive? Avoid algae? Slow, consistent growth? Red reds? Short internode length on stems? Growth maximization?
Best management practice.
One where managing CO2 and fish health, algae and ease of keeping the plants yields the highest % of success for a nice scaped tank and with the widest no# of species for the largest % of aquarist.
We cannot ignore fish and general care /labor from the aquarist.

In otherwords, let me turn this around on you:
What is the maximum no# of fish that you can possibly add to the tank?
What is the most amount of food can you feed them?
What is the max growth rates can I obtain with the fish?
What is the best CO2 level for fish?

Is "more" wise/better and even should it be suggested to the general hobby this way??

Perhaps for specific folks who might enjoy playing with fire or experienced folks with specific goals. However, for the average folks that includes say 90% or more?

To say that 4xT5HO is "too high" light for anything under 32 inches of depth is extremely conservative to say the least (ditto for many other examples, such as 2xT5NO over a 12" tank with no co2 or ferts), and seems to be at odds with lots of successful tanks (with varying concepts of success) on this forum.
Just because someone happens to have more light does not imply that (they have measured it??) it required for their results. If they measured it and reduced it down to see what their minimum might be, then you can say something, argue for it etc.

I know of no scape or plant I cannot grow WELL under the light chart Hoppy suggest, not one species.

I couldn't imagine trying to keep high light plants under just 2x54w @ 24". I use 4x54w and don't keep "high light" plants. Ditto for when my tank was 20", not 24".
I honestly do not quite know what a "high light plant is"
What is the min amount required?
Do you know the answer?
Is it independent of nutrients and CO2?
How would you confirm and calibrate the CO2 method?

This is not as easy to answer as it might seem.

You have to try it and see, if someone can show they grew the plant at say 30 micromol and you could only do it with 60, then your claim would be falsified. You can say that was the lowest you where able to do so....but you cannot say it is the lowest, the no#'s Hoppy and I suggest often times are the lowest we have observed..........they might be lower even still.........

That remains untested and demonstrated.
When someone claims that x species cannot be grown at less than say 50micromoles, this is a very easy question for others to test and confirm or falsify.

All it takes is one or two folks and that hypothesis is cooked and refried.

I know I've said similar things in the past, but I like to repeat myself, and there's a new representation in this chart of what seems to me to be well-intentioned, but oversimplified if not misleading advice.
Well, that is a trade off, I think we all like simple easy to understand things.
However, when this is done.......there are things that get left out of the model.

That is the very nature of simplifying complex things.

What might you suggest constructively that would not be too complex and yet useful to add to the chart?
Better Hoppy than me I say:) He wants to do it, has the passion to make and share these charts etc......bully for him, I have the meter so I'm happy.

Look, this is 100X better than W/gal or watt/gallon converters I've seen.....but I understand many are not going to use/buy PAR meters also, so this is the next best thing, but I like to use a meter and test myself. I'm curious and ignorant of how low we can go.........and we also know that lower light requires less CO2 and nutrients, which inherently implies........ easier management.

Hence Hoppy's advice for the chart.
Intermediate folks, they can mess around more if they chose.

No one is suggesting otherwise here.
 

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Ok, I'm going to go against the grain and say this experiment is dubious, and needs extensive clarification.
Even a typical uneducated hobbyists like myself seems to find them pretty easy to read.......

Why aren't the types of reflectors and specific models listed? What defines a "poor" reflector?
In some cases this information is simply not available as to brand of reflector, but they could be added, but this can make the charts a lot more messy. Any distillation of information will sacrifice some data in order to simplify.
Do we need such rigor? What is the goal?

We are simply trying to improve on the old method of Watt/gallon, which this has done very well and Hoppy has put the effort into creating and measuring out. Perfection? Never, better and closer to perfection? A little bit. Certainly better than the old alternative.

While the results presentation looks pretty, the procedures are undocumented and rather hand wavvy (no, I'm not talking about t-values either).
Why not ask Hoppy directly about the methods? Be a "guide" to improve the methods since you have such awesome creds, no? You have not done that but had enough gumption to post. Offer up some good methods then.

I have worked as a researcher at several prestigious labs. So I do have higher standards when reading and analyzing results.
What does this have to do with screaming howler monkeys flying out my rear?
Why would you inject this steer manure into this?

If you are this good, then why have you not done your own table and testing? Why have you not offered a better set of methods? You need to offer more than mere complaints...you need to offer solutions to the problems and issues you have with the table and methods.

Taken alone, these results do not make sense to me.
Taken alone, I find little issue with the chart, it can be off, as can any model ..........that distills and generalizes data. 300-400$ light meter vs the chart? Most hobbyist will go for the chart. The Meter is a back up and used often in clubs for more specific precise examples, test etc. I adjust my intensity and do a fair amount of set ups and can rationalize the meter for myself. But if Hoppy wants to knock himself out with it and make these charts, I ain't got no beef with it. Better him than me I say:thumbsup: If he's got a question or wants some input, he'll ask, or pose a question of an unexpected result. If I see something wrong, I'll say why and what might be a better method to answer that question......and the trade offs as far as a hobbyist may face trying to get that data/measurement etc.
 

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@Hoppy

Since you and Catalina are in the same city why not drop by with a PAR meter and measure his fixtures. His T5HO fixtures use ballasts which work fine to drive NO bulbs at proper levels.

I'm sure Jim would be glad to do so.

Just a thought

jim
I already loaned him the PAR meter, but they have not said much to me since. He's got work and employees to deal with, so it could be awhile.
 

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WOW.....I never thought people would get so up in arms over this matter. Hoppy has done a great job trying to help out the hobby by giving up his free time to give this forum a great tool to ESTIMATE what type of lighting we will need over our pride and joys. The bottom line is if this chart doesn't work for you then try something else! If you want to try raising your light 2' from the top of the tank....cool. If you want to try 1" from the top....go for it. IMO this will never be an exact science.....it's close.....but not exact.

If you think you have something of value to offer this forum then please do.

Thanks again Hoppy!
There'd be no hobby if it was all about +/- 5% ppm or umol.

Many have attempted to argue and bemoan that it is required, only to be falsified time and time again in abject failure.
Then the "back tracking" begins.

Rather than taking that approach, a good question is much wiser and more instructive. Over what range(max/average mid/min) can aquarist grow plant species X,Y, and Z of umol of light?

How does depth influence this with X, Y, and Z brands/light configurations?

These are questions that aquarist can do and answer that applies to their needs. No, not everyone will be able to grow say Syg "belem" at 30 micromols, but all it takes is one person to provide a nice example of this to lower the effective min lighting requirement.

Same with another species etc.......we know some of the upper ranges are going to be in the 400-600umol ranges.........which few except a few Reef folks might have.

While 30 might work if the nutrients and the CO2 are optimal, we will want to add some wiggle room for these NOT being the best all the time, so instead of 30, we suggest say 40-50 umol.

No need to be on the razor's edge, same for CO2, same for nutrients for that matter.
 

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I may have misread the chart a bit, seems I'm likely closer to 25-30 PAR. In any event, I have no desire for very rapid growth, using more co2 and ferts, nor increased algae risks.

My only real concern is that at 25-30 PAR, I've not got enough light for my ludwigia repens, rotala rotundifolia, and my narrow leaf microswords.
Well, adjustment without an open top style wire suspension is tougher.......
You can add more, then dial it to about 50 by raising the light.
The problem is that many cannot adjust their lights up or down much if at all.

So getting the sweet spot for PAR is tough. Most all ADA tanks are.....open top I think for this reason, as are my own tanks, but I do this more for ease of horticulture and working on the tanks, and the aesthetic.

25-30 is a bit on the lower end......microswords are fine...but most want a bit more for those 2 stem species to garden them well.
 

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Hoppy, you might want some of the data from the ATI fixtures I have, they make the Tek look like the PC vs the T5 lighting curves.

At 24" I'm reading 140-200 umols etc. Which if you look at the T5 graph........is kicking its butt.
 
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