How Do I Find Out My Tank Lighting, Low, Med, High? - The Planted Tank Forum
Old 02-22-2013, 01:47 PM Thread Starter
Planted Member

Join Date: Feb 2013
Location: London
Posts: 154
How Do I Find Out My Tank Lighting, Low, Med, High?

Hi

So I asked a question a couple of days ago asking how much Light is in my tank, I got the answer of Medium.

So as I am learning about plants in the aquarium I thought I want to learn how they figured it out, I'm not that clever so I try to keep things simple lol. But I googled aquarium lighting guides to try and learn more about lights, I found a site which told me how to calculate my light "http://www.fishkeeping.co.uk/article...r-aquarium.htm" the equation is at the bottom.

I followed the equation the best I could and in the end I worked out my tank has 3600LUX and I was aiming for 24,200 lux which would be med light... 3600LUX that's not even in the LOW light figures that he gave, either I did it all wrong, or his info is wrong, but either way if its true then I can't understand why my tank lights claim to promote plant growth. I know they can because I have had plants that grew and still do.

I also have read the post on here about using a Quantum PAR meter I cant afford that and don't want to get to technical I just want to understand a bit more about lights so if I went out and purchased a new tank I could calculate the lights that come with it and be like right that's a high light tank or that's a low light tank. Obviously I know T5's etc are all better than T8's.

So where can I learn all this? does anyone know a good place for me to start reading basic stuff about lighting in the tank.

Regarding the equation above I used, here is the specs of my tank.

Fluval Roma 90L - 20 Gallon
Width: 60cm Height: 45cm Depth: 35cm

Like I said I did all the maths on the site, and 3600 Lux sounds pretty laughable if its true, and I read the Lux on my bulbs, which are:

T8 - Aqua Glo 15w Lux 35
T8 - Power Glo 15w Lux 50

That's a LUX of 85 which is even lower than 3600 LUX... I'm starting to think my torch would be better.

They also say Aqua Glo has a lumen of 290 and Power Glo lumen of 580..
I am aiming for lets say the med light which was 24,200... add mine up and you get 870 lumens.. I am so confused about everything right now, all I want to do is learn a bit about lights and how I can work out roughly how much light is in my tank with out to getting to technical. Other people worked out my tank to be MED light but how did they do that.....

I also see a lot of people with my tank doing DIY on there lights as apparently its so bad... but I'm not very good at DIY.. I cant find anything that would work on my tank.. I looked everywhere and because the top of the tank has a plastic case.. you cant even clip a new light set or anything.. But I don't mind low growing plants.. just wish I understood this all a bit better. Thanks for any help on this... I would really appreciate it. It's just hard to take it all in.
Jafooli is offline

Old 02-28-2013, 12:50 AM
Planted Tank Enthusiast

Join Date: Jun 2012
Location: NE TN
Posts: 588
Interesting reading but not sure I agree with some of the conclusions. Or else I'm not quite getting what he's saying. For example, he was stating he wanted medium high light (33000 lux) in his tank which has the same dimensions as a USA 75 gallon tank. Using T8 he stated he would need 302.5 watts (with lid), which for 48" tubes would equal almost 10 tubes since they are 32 watts each.

I have 2-T8 bulbs with good reflectors on my tank. I used a Lux meter in open air to measure my fixture and at 25" height the lux as measured at the center of the fixture was around 2950-3000 .. to get PAR that number is divided by 76. So I figured I'd have approximately 38-40 PAR if I hung the fixture about 25" from the substrate. That puts it in the low end of medium light according to Hoppy's definition located in this thread: Lighting an Aquarium with PAR instead of Watts. If I had 2 of these fixtures (Diamond Plate T8) I'd get approximately 80 par .. high light but only have 128 watts... 4 bulbs x 32 watts each = 128 watts. No where close to the 302 watts he stated was needed for high light. And if we can use the lux/par conversion on his figures, 33000 lux would be about 434 PAR!! Or maybe I didn't follow or understand all those numbers & calculations on his site.

However, you say you calculated you have about 3600 lux which if we use the lux to par conversion and divide your lux by 76 we'd get 47.4 PAR which puts you in medium light. And depending on how high your fixture is from the substrate this sounds like it could be fairly accurate. For some reason my brain wouldn't let me figure out my Lux from that site so I could see how it compared to what I actually measured.

Hopefully someone else will chime in with their opinion.
sowNreap is offline
Old 02-28-2013, 06:51 PM
Planted Tank Guru

Join Date: Dec 2005
Location: Sacramento, CA
Posts: 20,733
The author of that article is confused! He apparently didn't grasp the difference between lumens and lux - lumens are the total light emitted by the bulb, in all directions, while lux is the light per unit area on the surface being lighted. They are apples and oranges. He says that no reflector can double the light from a bulb, but I have measured the light with and without a simple \_/ shaped reflector, and the reflector did double the light, even though it wasn't even polished. Then he misplaced a decimal point when he listed the lux needed for low,medium and high light. It was a good try at explaining light intensity, but it is not correct.

Hoppy
Hoppy is online now
Old 03-01-2013, 05:43 AM
Planted Tank Obsessed

Join Date: Sep 2010
Location: havre de grace, MD
Posts: 333

"So where can I learn all this? does anyone know a good place for me to start reading basic stuff about lighting in the tank."

You are in the lighting forum already, good job. Cruise through the various threads and find ones which have a lot of responses. When you see a high number of responses, read the title and decide whether or not you can learn something new by reading that thread.

I realize I'm not giving you a direct number, e.g. high=22 posts. that's because you will decide what a "high" number is, after you've read through a couple posts.

Yes, I'm telling you to judge a book by it's cover. But with online forums, the cover has statistics by it which will give you an idea as to whether or not there is useful information there.

Don't stress too much over lighting. Start with easy plants (java fern, anubias, crypts, almost any kind of tall grasses) and as you grow more comfortable, you can try more difficult plants. Honestly, you may end up sticking with the "easy" plants because they do everything you want them to do. Aquascaping skills will outweigh aquagardening skills any day of the week if all you want is a beautiful aquarium.

Finally, the amount of light drives the plants to grow more quickly or less quickly. If they grow fast, they need nutrients to support their growth. You know the law which says "the same amount of matter and energy will always exist in the universe" (Newtonian?) In other words, matter isn't destroyed when it's burned, it just gets converted to energy, which later gets turned back into matter. Or can get turned into matter. Whatever. Well, along those lines, plants build themselves with something that's in their environment. C02 is needed for high light aquariums because other wise it's like someone who's genes say he should be seven feet tall, but is living on nothing but cheerios and diet coke.

What does my rambling mean? It means simply this-- EVERYTHING wants to not just survive, but to THRIVE. If your plants aren't thriving, ask someone. If your plant's arent thriving, but your algae is, GREAT! You can successfully grow algae! We can build to plants from there. Don't sweat the small stuff, and enjoy your aquarium.

--I hope this all makes sense. If not, I apologize. It's been a rough day, week, and couple months for that matter. Writing soothes me, so thank you for being my stress outlet!

As a matter of fact, yes, I always post, or reply, in novels. I'm adding it to my signature because it seems like I say it in every post!
Fraternity of dirt #32 I'm dirty
UGLY TANK
DIY Asian themed aquarium stand

Last edited by moonshinetheslacker; 03-01-2013 at 05:45 AM. Reason: typo
moonshinetheslacker is offline
Old 03-02-2013, 11:35 PM
Planted Tank Enthusiast

Join Date: Jan 2013
Location: Boston ma
Posts: 741
Quote:
Originally Posted by moonshinetheslacker View Post

"So where can I learn all this? does anyone know a good place for me to start reading basic stuff about lighting in the tank."

You are in the lighting forum already, good job. Cruise through the various threads and find ones which have a lot of responses. When you see a high number of responses, read the title and decide whether or not you can learn something new by reading that thread.

I realize I'm not giving you a direct number, e.g. high=22 posts. that's because you will decide what a "high" number is, after you've read through a couple posts.

Yes, I'm telling you to judge a book by it's cover. But with online forums, the cover has statistics by it which will give you an idea as to whether or not there is useful information there.

Don't stress too much over lighting. Start with easy plants (java fern, anubias, crypts, almost any kind of tall grasses) and as you grow more comfortable, you can try more difficult plants. Honestly, you may end up sticking with the "easy" plants because they do everything you want them to do. Aquascaping skills will outweigh aquagardening skills any day of the week if all you want is a beautiful aquarium.

Finally, the amount of light drives the plants to grow more quickly or less quickly. If they grow fast, they need nutrients to support their growth. You know the law which says "the same amount of matter and energy will always exist in the universe" (Newtonian?) In other words, matter isn't destroyed when it's burned, it just gets converted to energy, which later gets turned back into matter. Or can get turned into matter. Whatever. Well, along those lines, plants build themselves with something that's in their environment. C02 is needed for high light aquariums because other wise it's like someone who's genes say he should be seven feet tall, but is living on nothing but cheerios and diet coke.

What does my rambling mean? It means simply this-- EVERYTHING wants to not just survive, but to THRIVE. If your plants aren't thriving, ask someone. If your plant's arent thriving, but your algae is, GREAT! You can successfully grow algae! We can build to plants from there. Don't sweat the small stuff, and enjoy your aquarium.

--I hope this all makes sense. If not, I apologize. It's been a rough day, week, and couple months for that matter. Writing soothes me, so thank you for being my stress outlet!
For some darn reason I understand everything u say here. Lol
newbieplanter is offline

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