# HOW TO Calculate your tank lighting (in LSI)



## Hoppy

Isn't it self evident that if you put 108 watts of T5HO bulbs over a 55 gallon tank the amount of light you get depends on how good the reflectors are. All of the lumens produced by the bulbs do not reach the tank unless you have good reflectors, so more than half of the lumens are wasted if those are just bare bulbs. Any calculator of this type just has to include a reflector factor to be of any use at all.


----------



## dtejeda.arias

Great article. I need to read this several times to master it.


----------



## ucrdave

Hoppy said:


> Isn't it self evident that if you put 108 watts of T5HO bulbs over a 55 gallon tank the amount of light you get depends on how good the reflectors are. All of the lumens produced by the bulbs do not reach the tank unless you have good reflectors, so more than half of the lumens are wasted if those are just bare bulbs. Any calculator of this type just has to include a reflector factor to be of any use at all.


Yes, having a reflector factor is necessary, however I cant calculate my way toward a factor and have confidence in the result. If I were to have measurements, then I could calculate a factor for specific types of reflectors. This kind of information would then allow calculators such as these to be much more useful.

**EDIT** General fudge factors have been put in place for the manual calculation, however they are not included in the auto calculator untill confirmation of my factors seem reasonable. These changes should make your example go boom into the wind (╯°□°)╯︵ ┻━┻

If one understands that with different reflectors one can increase or decrease the intensity of light over a surface, then one could subtract or add more lumens from ones' total to achieve a calculation with more confidence. Unfortunately, many people do not understand which factors affect the final outcome. PAR meters take the guess work and laborious calculation off the table. :biggrin: With PAR meters we can see great work in compilation of measurements such as yours and others on this site.

Hoppy (or anyone), can you direct me to a link that gives some basic factors for the most common reflectors for t5HO fixtures that are trusted by many? I would like to include it in the calculator and main body of this thread.

I hope that the manual calculation in this post helps to make this calculation approachable...


----------



## cooledwhip

Hey all. I am calculating my aquarium light for a 2.5 gallon aquascape and I am somewhat new to the hobby and don't really know much about lighting so I wanted to ask a question on this thread. I downloaded the calculator but I don't understand what the numbers mean after reading this post many times and even printing it out.

I plugged in my dimensions, and got the Lux @ Depth to be 43461. I changed the bulbs number to 1 bulb at 60 watts because I plan on using a desk lamp.

Basically I don't know what those numbers mean but I will also give a bit of back story here:

Last night I bought a 6500K CFL by Sylvania. Apparently it was a 60w that only uses 13w or something. I put it in my desk lamp and it provided light for about 10 minutes then I heard a fizzle and it shut off. Now the bulb doesn't work anymore?? I have no idea why. I have another one, I don't know if it was the fact that the bulb was too powerful for the lamp or vice/versa.
I plan on growing dwarf hair grass and dwarf baby tears in this tank so I need lots of light. I will use CO2 and dose plant food.

I know nothing about lighting. The lights in my other tanks are LED's but people said that the LED's wouldn't work when growing plants like DHG and DBT.

Thanks!


----------



## ucrdave

In general, if a tank is small 5 gallons or less) calculators break down. For a take that's 2.5 gallons you need very little light!even 13 watts is too much. You could use a ~ 6 watt or less over your small tank and it should be sufficient. 13 watts is over kill. 

BTW LEDs can grow grownd cover. I've grown them before as well as HC and HM plants with LEDs. Lights aren't the only factor to growing plants . water chemistry, substrate, lights, etc all account .


----------



## cooledwhip

ucrdave said:


> In general, if a tank is small 5 gallons or less) calculators break down. For a take that's 2.5 gallons you need very little light!even 13 watts is too much. You could use a ~ 6 watt or less over your small tank and it should be sufficient. 13 watts is over kill.
> 
> BTW LEDs can grow grownd cover. I've grown them before as well as HC and HM plants with LEDs. Lights aren't the only factor to growing plants . water chemistry, substrate, lights, etc all account .


Thanks for fast reply. Yeah I have seachem flourite, I will dose seachem flourish. For a small tank like a 2.5, would any light really work? Thanks.

Would a generic LED strip from amazon work?


----------



## ilv2grdn

I have had traditional tank (gravel and plastic plants) on and off, for 20 years. At this time, I've had it up and running for 4 years now. Last year I started watching planted tank videos and caught the bug. I am avid gardener outside so wanted to expand my growing capabilities. I am completely new to this and have a lot of learning to do. 

Before knowing anything about lighting, I purchased an LED strip to make a DIY lighting hood out of white rain guttering. After completing this I was anxious to see what it looked like so I put it on my old tank before I tore it down. I was very disappointed. Thought it seemed very bright outside the tank, but it was very dim on the tank. Even on the highest setting. Enough to where I had to add my original lighting fixture of two fluorescent grow lights. Also, this LED strip came with no info about wattage or anything needed to calculate amount of light. This is what I bought. And I assure you, I did not pay that for it. They raised the price like 500% after I bought it for $25. 

http://www.ebay.com/itm/121242648193?_trksid=p2057872.m2749.l2649&ssPageName=STRK:MEBIDX:IT

I was wondering if any of you had any experience with these LEDs and/or could tell me what I've done wrong or what I need to get. My tank is 48Lx 18wx 22d. Already have plants waiting in a 10 gal and driftwood that's been soaking for a month. The old tank has been tore down and my fish are also waiting in that 10gal. Am in the process of scaping and will probably fill with water hopefully by tomorrow. For now, will have to use both LEDs and flourescents till I get something else figured out. Kind of jumped in before I was completely ready. lol

Also, do all LEDs give of a blue hew even when on white setting? The tanks that I've seen online don't look blue.

Please, help? Thanks


----------



## jeffkrol

ilv2grdn said:


> I have had traditional tank (gravel and plastic plants) on and off, for 20 years. At this time, I've had it up and running for 4 years now. Last year I started watching planted tank videos and caught the bug. I am avid gardener outside so wanted to expand my growing capabilities. I am completely new to this and have a lot of learning to do.
> 
> Before knowing anything about lighting, I purchased an LED strip to make a DIY lighting hood out of white rain guttering. After completing this I was anxious to see what it looked like so I put it on my old tank before I tore it down. I was very disappointed. Thought it seemed very bright outside the tank, but it was very dim on the tank. Even on the highest setting. Enough to where I had to add my original lighting fixture of two fluorescent grow lights. Also, this LED strip came with no info about wattage or anything needed to calculate amount of light. This is what I bought. And I assure you, I did not pay that for it. They raised the price like 500% after I bought it for $25.
> 
> [Ebay Link Removed] 16 4ft LED SMD 5050 Strip Flexible Light with Remote and Power Supply | eBay[/url]
> 
> I was wondering if any of you had any experience with these LEDs and/or could tell me what I've done wrong or what I need to get. My tank is 48Lx 18wx 22d. Already have plants waiting in a 10 gal and driftwood that's been soaking for a month. The old tank has been tore down and my fish are also waiting in that 10gal. Am in the process of scaping and will probably fill with water hopefully by tomorrow. For now, will have to use both LEDs and flourescents till I get something else figured out. Kind of jumped in before I was completely ready. lol
> 
> Also, do all LEDs give of a blue hew even when on white setting? The tanks that I've seen online don't look blue.
> 
> Please, help? Thanks


SMD505's are practically useless for that size tank w/ out a REAL high density.. 
RGB LED's arguably have huge holes in their spectrum compared to "white" led's
A mix of ww/cw 5630 .5W Led's is your "best shot" at anything strip wise..

non-waterproof example..
Amazon.com - 360deal 5m16.4ft Hot Sale SMD 5630 White 300 LED Flexible Strip Light 12v Brighter than 5050 - String Lights

your blue tone is from using RGB to emulate white.. Just doesn't work so well..

This would work:
http://www.aquatraders.com/LED-Aquarium-Lighting-EVO-Freshwater-Plant-p/56547p.htm

more options if you define what you are willing to spend and what you want them to do.


----------



## ucrdave

.5 watt LEDs are a minimum for most light fixtures to be viable cost wise. I'd suggest finding something on eBay or amazon. I purchased my 155 watt high power led adjustable color temp fixture from eBay. I of course have the lights set to a lower than max setting.


----------



## fishyfishy101

I'm in the process of upgrading my light from low to medium, and according to this what I was planning on doing is still in the very low light range. So if it's correct, that's very disappointing.


----------



## ucrdave

How many gallons is your tank?


----------



## jeffkrol

As to reflectors there are "bits and pieces" of info everywhere on "the google".. 

Equipment Review: Getting the Most from Your T-5 Lights: A Look at Reflectors and More ? Advanced Aquarist | Aquarist Magazine and Blog


----------



## ilv2grdn

Thank you so much jeffkrol. Great info.I did not know that. I always thought the RGB would be better at being full spectrum than the white. I'm trying to stay as low cost as I possibly can. So that 360deal 5m16.4ft Hot Sale SMD 5630 White 300 LED Flexible Strip Light sounds like the way to go for me. Thank you! That one that I used was 16' it made 4 passes back and forth along the rain guttering. Now if I bought two of the ones you suggested, would that double the brightness? Or would it stay the same, just more of it... if that makes any sense. lol I'm going for a low tech, low to med light, dirted tank, no CO2. 

That info about reflectors was great too. Had no idea. I was going to paint the back black or a dark blue. Forget that. Now I think do a light blue plastic taped on. Since these are LEDs not bulbs, should I still have reflector on the hood? I am learning so much but have many miles to go. 

Almost forgot... my tank is 76 gal. Funny story. I originally had a 55 long is what I've had set up all these years. This time I had it set up for 4 years and it finally decided to spring a leak. Woke up and stepped in water. Grrr. Went to a local mini mart trying to give my fish away, when a lady walked in and said she had a 50 gal I could have. I was so relieved. I was going to make the change to planted tank but wasn't quite ready for that yet. So I am kind of rushed. That's where I'm at right now. Oh, by the way, that "50 gal." tank she gave me turned out to be 76. With it's own cabinet and everything. A very expensive setup. She just gave it to me to get it out of her garage. Right place, right time, I guess. Never had one that big before though I've always wanted one but could never afford it. (haha) Just to be safe my husband reinforced the floor.  Could've asked for that to turn out any better! Thanks again...I off to hardscape.


----------



## jeffkrol

ilv2grdn said:


> Thank you so much jeffkrol. Great info.I did not know that. I always thought the RGB would be better at being full spectrum than the white. I'm trying to stay as low cost as I possibly can. So that 360deal 5m16.4ft Hot Sale SMD 5630 White 300 LED Flexible Strip Light sounds like the way to go for me. Thank you! That one that I used was 16' it made 4 passes back and forth along the rain guttering. Now if I bought two of the ones you suggested, would that double the brightness? Or would it stay the same, just more of it... if that makes any sense. lol I'm going for a low tech, low to med light, dirted tank, no CO2.
> 
> That info about reflectors was great too. Had no idea. I was going to paint the back black or a dark blue. Forget that. Now I think do a light blue plastic taped on. Since these are LEDs not bulbs, should I still have reflector on the hood? I am learning so much but have many miles to go.
> 
> Almost forgot... my tank is 76 gal. Funny story. I originally had a 55 long is what I've had set up all these years. This time I had it set up for 4 years and it finally decided to spring a leak. Woke up and stepped in water. Grrr. Went to a local mini mart trying to give my fish away, when a lady walked in and said she had a 50 gal I could have. I was so relieved. I was going to make the change to planted tank but wasn't quite ready for that yet. So I am kind of rushed. That's where I'm at right now. Oh, by the way, that "50 gal." tank she gave me turned out to be 76. With it's own cabinet and everything. A very expensive setup. She just gave it to me to get it out of her garage. Right place, right time, I guess. Never had one that big before though I've always wanted one but could never afford it. (haha) Just to be safe my husband reinforced the floor.  Could've asked for that to turn out any better! Thanks again...I off to hardscape.


most LED's ar "naively" lensed at around 120 degrees so reflectors are not necessary..

rgb spectrum:









warm white to cool white led


----------

