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RedMenace New Members
Joined: 30 Apr 2005 Location: Taichung, Taiwan
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Posted: 2005.05.04(Wed)7:13 Post subject: Do I have too much light? |
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When I bought my first tank, a little 8 gallon (45x24x33), the fish store sold my a light that says 36 watts Daylight on the tube. This works out to 4.5 watts per gallon. This seems higher than the recommended levels I've seen.
Will this cause any problems? I've got my tank fairly heavily planted, some plants are growing, others seem pretty dormant. I'm getting more algae than I would like, but it's not that big of a problem yet. I'm not adding CO2, but I will consider it as soon as I figure out how it works with the pH and and such.
Thanks for any advice. |
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number6 Moderators

Joined: 07 Feb 2003 Location: Ontario, Canada
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Posted: 2005.05.04(Wed)8:37 Post subject: |
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ignore watts per gallon. 36w of light total is a moderate light tank. You are still short several watts for a high light setup like you'd see in an Amano setup. _________________ Discus Man is gone... I remain... #6... I am not a number I am a free man! |
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Laskey Benefactors

Joined: 27 Nov 2004 Location: Northern Germany
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Posted: 2005.05.08(Sun)7:30 Post subject: |
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I'm no expert but in a small tank, isn't the intensity at the bottom significantly higher, by virtue of the fact that the tank is shorter?
I've never heard to disregard watts-per-gallon, but would love to be re-educated on the matter. I always assumed that my 40 watts in a 29-gallon was medium-lit. The salesman at the LFS told me on Friday, "That is not a low-light tank, and you should be buying high-light, fast-growing plants". (And then I'd assume I'd need CO2 and a more regular dose of fertilizer, because when I tried high-light plants in the past, they always failed to grow and got algae on them. At the time I just thought my lighting was inadequate at about 1.3 - 1.4 watts per gallon).
Hmm.
Laskey |
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Rex Grigg Members

Joined: 26 Feb 2005
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Posted: 2005.05.08(Sun)7:52 Post subject: |
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The WPG rule does break down on small and large tanks.
Here is the extreme example. A one gallon nano-cube with a 4 watt light in a dark room providing no ambient light. You have 4 wpg but I know you will not be able to grow high light plants. There is a minimum light energy needed by plants that is not adequately expressed in the WPG rule when it comes to small tanks.
I cover my thoughts on this subject more throughly on my web site.
Laskey, with 40 watts over a 29 gallon tank you have a low light tank. Been there, done that. I now have 110 watts over the same tank. It makes a huge difference. As did the intermediate step of 65 watts. _________________ www.rexgrigg.com
Semper Fi |
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anonapersona Advisors
Joined: 06 Feb 2003 Location: Houston, Texas
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Posted: 2005.05.08(Sun)9:50 Post subject: options |
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I'd say that was high light. CO2 and ferts are the key.
You have some options, you can start looking at the fertilization to be sure you are pumping in enough to let the plants take care of the ligting before the algae does. You can add supports under the light to raise it a bit. You can dim the light that hits the water by letting the glass get dirty. You can add surface floaters to block some light from the water. You can reduce the hours of lighting, drop down towards 10 hours from whatever you have now. |
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Laskey Benefactors

Joined: 27 Nov 2004 Location: Northern Germany
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Posted: 2005.05.08(Sun)9:56 Post subject: |
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| Rex Grigg wrote: |
Laskey, with 40 watts over a 29 gallon tank you have a low light tank. Been there, done that. I now have 110 watts over the same tank. It makes a huge difference. As did the intermediate step of 65 watts. |
Thank you, I've tried many different kinds of plants and even DIY CO2 for a couple of weeks and let's just say I don't know why the salesman said what he said. Cabomba caroliniana and sagittaria pusilla are my fast-growers in medium-light but I dare not try something that demands high-light. If anything, I just left my lights on too long and that's why my slower-growing plants got algae and even "burn spots" on them. I'm testing that theory.
As for the original poster's question, I don't want to go against the moderator's advice but it does seem like a lot of light for 8 gallons. I would worry about burn spots on the plants and a whole world of algae considerations if the lights were on for what we consider a normal amount of hours. It could work with the right levels of nutrients and CO2 but the lighting in that tank almost sounds problematic; I wouldn't be surprised if he/she has burn spots on high-light plants from leaving the lights on for more than 6 hours.
I'll pay attention to this thread and see what can be learned. Even though the original poster's question would be the opposite, I'm curious about this lighting question.
Laskey |
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Rex Grigg Members

Joined: 26 Feb 2005
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Posted: 2005.05.09(Mon)6:26 Post subject: |
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It's not that much light for an 8 gallon tank. I know people running 72 watts over a 10 gallon tank. That's high light. 36 watts over an 8 gallon tank IMHO would be medium light. And it does put you in the area where CO2 is needed. _________________ www.rexgrigg.com
Semper Fi |
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RedMenace New Members
Joined: 30 Apr 2005 Location: Taichung, Taiwan
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Posted: 2005.05.09(Mon)8:43 Post subject: |
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This is the OP again. I haven't noticed any burn spots yet, but algae is becoming an issue. Green spots are slowly appearing on leaves and glass, it still looks really good, but if it gets much worse it will be a problem. I'm still learning about aquariums, it's only been a couple months since I started without a clue. The gist of what I've learned from the internet about controlling algae is to try and encourage plant growth to outcompete the algae. So I've fully planted the aquarium, and in my opinion it's beautiful. Last weekend I made DIY CO2. I left it on all day the first day, and I actually noticed some real plant growth in a single day. But that night I noticed one of my cories in a daze at the bottom of the tank, and I expected him to die. He was fine in the morning. I'm not really sure how to regulate DIY CO2, so I've just been sticking it in the tank periodically the last couple of days.
Anyways back to the lighting. I've been leaving them on about 10 or 11 hours a day, and like I say, I've seen no burn spots. I don't really know what a burn spot looks like, but I'd probably recognize one. I really want to stop this algae growth. Would you advise leaving the lights on for a shorter period? Any other advice would be greatly appreciated as well.
By the way the lights are the kind that clamp on to the back and can be extended at all angles over the tank. This gives me the option of raising or lowering the lights. Would this make a difference?
Thanks a lot! |
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Neon New Members

Joined: 07 May 2005 Location: Russia, Moskow
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Posted: 2005.05.09(Mon)8:54 Post subject: |
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To light at you, really, much. It is necessary to know that for plants raise. If Glossostigma light is sufficeed with 2,1 watt on 1 gall. If Anubias light should be weak, a penumbra. You have written nothing about plants.
Seldom change water, feed much. High parameter pH of water (more than 7.0) Is the main reasons. Probably there are lost plants?
To reduce light day 9 hours per day are lower is not recommended. The plant will not have time to develop a chlorophyll.
It is necessary to know, that bright light and high temperature, demand some the raised(increased) fertilizer for plants and submission |
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number6 Moderators

Joined: 07 Feb 2003 Location: Ontario, Canada
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Posted: 2005.05.09(Mon)9:25 Post subject: |
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| RedMenace wrote: | | Anyways back to the lighting. I've been leaving them on about 10 or 11 hours a day, and like I say, I've seen no burn spots. | They are fluorescent lights right? When you say clip on lights I am wondering if you are using halogen or incandescant.
Algae is outcompeting your plants right now. The CO2 will ehlp, it helps all but very low light tanks. You cn't regulate DIY CO@ except through the mixture. Add less yeast. Cut in in half. The mix will last 2x as long by producing 1/2 the CO2. Each yeast divides a certain number of times then stops. Add less, lowers the total population.
I would recommend adding more light. At such low light, you'll never burn the plants. I have 50w NO Fluor. over a 10g right now and I am thinking of increasing it.
anonapersona, it really isn't a high light. You should look into Amano tanks to see what light levels he uses to achieve high light on a small tank. _________________ Discus Man is gone... I remain... #6... I am not a number I am a free man! |
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