# Sticky  Light Chart- Low, Medium, High? Your answer!



## grogan

This is the chart that is used for the most part by the planted community, including myself. Basically, the 'watts per gallon' rule is no longer used. This chart is based off of Parr values. Essentially the bulb efficiency and reflectors on the fixture. 

Courtesy of Hoppy on the Plantedtank.net 









This is an older version of the chart. Rather than measuring the tank height, go by the substrate height. For example my 56 gallon is 24" tall. I have my light mounted 12" above the aquarium, giving me a total height of 36". According to this chart my tank my tank has low light. However I have and average of 4" of substrate in the aquarium. If I subtract the 4" from the total tank height that gives me 20" total tank height. With a dual bulb T5" fixture mounted 12" above the tank that makes it medium light. Not to much and not to little.


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## grogan

I love this chart because people always assume that with plants you need TONS of light. In actuality most aquariums will achieve high light with a decent dual bulb T5 fixture. Just remember that with fluorescent fixtures the reflectors really determine the efficiency, not the watts. Here is another chart from the same poster to determine reflector quality:









This plays a major role in interpreting this chart. The high light end is based off 'high quality' reflectors.


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## grogan

My lights


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## Murloc

True, you don't NEED as much light as one would think, or as much as was previously thought. A lot of the after market hoods / lamps are really for reef tanks. I, however, like to go heavy on the light, just because I can haha. I do like that chart, it doesn't cover my current tank though ( it being 36" tall, 3-4" substrate, 4" above tank ), BUT... Now that I have my Nano Cube out of storage, and sitting here being use as a quarantine tank.. I mine as well set it up right? A nice short dual T5 fixture... Maybe some LEDS to add an "actinic" spectrum to it.


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## grogan

The formula used in this chart can be applied to any tank. Look at the very last column. It says with a 24" tank and a ligh suspended 12" above the aquarium that gives you low light. So apply the same idea on your tank minus the suspend fixture. So a 36" tall aquarium with the light sitting directly on the surface would be essentially the same output. Both tanks have a total of 36" from the bottom surface to the light. so going off the chart a 4 bulb t5 sitting directly on the surface would be high light. With your substrate though I would elevate the light another four inches to compensate.


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## Murloc

grogan said:


> The formula used in this chart can be applied to any tank. Look at the very last column. It says with a 24" tank and a ligh suspended 12" above the aquarium that gives you low light. So apply the same idea on your tank minus the suspend fixture. So a 36" tall aquarium with the light sitting directly on the surface would be essentially the same output. Both tanks have a total of 36" from the bottom surface to the light. so going off the chart a 4 bulb t5 sitting directly on the surface would be high light. With your substrate though I would elevate the light another four inches to compensate.


Wow, I need my eyes checked haha. My light is about 4in from the top, so I should be in a good zone.


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## Redhead305

where do i stand with a 90g with 1" sub the tanks is 24" tall and http://www.amazon.com/Odyssea-Aquar...UTF8&colid=3UYB5NALEFHD2&coliid=ILJVUDVK633YF thats the light i have cept its 4 of the 10k bulbs


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## grogan

Well depending on your reflectors just add the substrate height to the calculations on the chart. 4 bulb T5? I thought you were going for a low light tank? If those are good reflectors that light is going to need to be suspended 12" plus. Compare your reflectors to the chart above and refer it to this chart:

Cutesy of Hoppy on plantedtank.net


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## Redhead305

lol i was going for fair medium just to have basic plants such as microsword, anacharis, bacopi and such


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## funlad3

:lol: In SW, our low light is no lower than 250 PAR. SW is a brighter hobby than FW.


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## grogan

hey go back to the salt threads you crawled out of!


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## grogan

Redhead305 said:


> lol i was going for fair medium just to have basic plants such as microsword, anacharis, bacopi and such


Post a pic of the reflectors and we will determine what you have. Its no biggie if its to much.. Just hang that light and get a CO2 setup, and join the ranks of "High Tech" planted hobbyist.


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## Redhead305

lol okay no prob true true i cant always just get dif plants


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## Obsidian

Okay you do the math! I am not sure how this works out, mostly because I am not sure about the reflectors. It's a 20Long, top of substrate to top of tank is 10.5 inches. Light sits on top. Light has a glass top that it sits on and it has a protective piece of plastic over the bulb housing.


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## grogan

Obsidian,
If you look at the reflector picture above you will see that exact light in the bottom right. It is a low quality reflector. I am almost positive that they are na t5s (normal output). So at 12" inches that gives you high/medium. So with ten Im going to go with the highest end of medium/low high light. They actually are not that bad of lights. I used them for several months on my 56 and had amazing results on a much taller tank.









Notice that Im using CO2. All high light tanks need this. With a medium light tank you can skate by with Flourish Excel, but a high light tank it simply will not cut it.


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## supatank

This is really interesting because i actually have the same light fixture (aqueon dual t5 light). Now my question is; wouldn't it be more beneficial to just take out one bulb, that way it will make use of the reflector since having two is crowding it, which renders it useless?


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## emc7

I doubt that would help. Say taking out a bulb improves the reflector up to 1.5X the 1 bulb, its still not as good as 2 bulbs. And having an open socket is an invitation to corrosion, shorts and shocks. It would only be safe if you removed the socket and rewired it.


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## aMawds

So I can't really read the graph for my situation. My tank is a 15 standard, so height is 12 inches. However I have about 3 inches substrate. Running a single T8 with a reflector that had plenty of room but was painted gloss white, so I improved it with some tin foil. Only reason I'm here asking about this is because my anacharis stems are growing off the main plants like mad, but then a lot of the time they seem to sort of turn away from the light. The closer they get to the light the more they seem to do it. Wondering if I maybe have medium light at this point and going into high when they're a couple inches from the fixture like that, thereby needing co2 at that level.


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## supatank

emc7 said:


> I doubt that would help. Say taking out a bulb improves the reflector up to 1.5X the 1 bulb, its still not as good as 2 bulbs. And having an open socket is an invitation to corrosion, shorts and shocks. It would only be safe if you removed the socket and rewired it.


let say it is 1.5x better for 1bulb. That still good considering how much energy i would be saving vers. 2bulb!? If that is the case, then i would be able to save even more energy if i bought two fixture and have 1 bulb in each; that would leave me room to spread the light evenly throughout the tanks and not have it stationary in either one spot or another. Isn't that what really matter at the end of the day, is to get the light out to all the plants? 
Corrosion wise...for what it worth, the fixture does come with a plastic splash protector.


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## emc7

No open sockets, just bad, bad. You've have to find a T5 plug. 

I believe anarcharis is a low or low-medium light plant. If the light is too strong, CO2 won't help, you need a different plant. Match the plant to the light. Like there are plants you plant in the sun and others in the shade, mix them up and both suffer.


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## grogan

aMawds said:


> So I can't really read the graph for my situation. My tank is a 15 standard, so height is 12 inches. However I have about 3 inches substrate. Running a single T8 with a reflector that had plenty of room but was painted gloss white, so I improved it with some tin foil. Only reason I'm here asking about this is because my anacharis stems are growing off the main plants like mad, but then a lot of the time they seem to sort of turn away from the light. The closer they get to the light the more they seem to do it. Wondering if I maybe have medium light at this point and going into high when they're a couple inches from the fixture like that, thereby needing co2 at that level.


Let me break the formula down for you sir. So you have 3" of substrate, simply add that to the formula. 

So a single T8 bulb with a decent reflector on 3" of substrate would give you 9" of tank height. Since this is below what the chart shows, my best bet is low-medium light. If you raise the light 3" it will cancel out the 3" of substrate and put your aquarium back on the chart. 

The basic idea is to measure off of the substrate and adjust the light accordingly.


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