# How much light should I start with?



## Deni (Jul 6, 2005)

I get really confused about how much light I need, especially since I'm working with a small 12-gallon tank.

I'm starting a new aquarium from scratch, including building the hood. At the moment I have a 1x15W T8 fixture and 2 2x15W T8 fixtures. (Neither of these have reflectors.) I could put one or any two of them in the hood, which means I could have anywhere from 15W to 60W without having to buy anything. I could also get one or two 36W CF kits.

I am willing to start out with low-light plants, but it's tempting to go for high light so I can include any plants I want. I need somebody to bring me back to earth.


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## aaronnorth (Apr 21, 2008)

As long as your tank is a minimum of 10gallons then the WPG rule will work out, anything less and you need more light. 

Aim for 1-2WPG for low light and 2-3WPG+ for high light. Once you reach 2WPG you will need to start adding co2 and the more light also means more nutrients. Go for 24w for low light then 36w for high light.


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## Deni (Jul 6, 2005)

Given what I have, I don't think I can come up with either 24 or 36W. I can do 15, 30 or 45.  I'm not sure whether it's preferable to go with a bit less and use the 15W to start with or to go with a bit more and go with 30. 

Then again, it's very likely that I'm over-thinking the whole thing.


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## aaronnorth (Apr 21, 2008)

meet half way and go with 30. 15w is low, you will only be able to grow anubias, vallis, egeria, java fern, hygrophilia, java moss.


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## cs_gardener (Apr 28, 2006)

On my 10 gallon low light, virtually no maintenance tank I had to put 2 of the standard 15 watt lights in order to grow the most hardy plants (java ferns, mosses, hornwort and Sagittaria subulata mostly and they grow slooooowly). So I'd say no less than 30 watts for your 12 gallon. 

Since you're doing it yourself will you have the option of turning the lights on individually? If so, it would give you greater freedom if you were to add the third light and use it for a noon burst or just have it in reserve if you want to get into plants that require more light in the future.


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## Deni (Jul 6, 2005)

I definitely plan to increase the light over time. I'm just thinking right now about what I should start with as I get things going without becoming an algae farm.



> will you have the option of turning the lights on individually?


Sorta, but not really. The 15W is one fixture and the 2 2X15W are individual fixures. So, if I wanted to have lights going on independently, I'd have to have a total of 45W or 60W.

The only thing I can really do independently with the 30W fixtures is to have two bulbs of different color temperature, so I can experiment with what looks good.

I could buy another 15W one, I suppose, which would allow me to have a total of 30W and independent switches. I just hate to buy more unless I really have to.

These are fixtures from Eclipse hoods. I started with a hood with a 15W bulb, then switched it to a 2-bulb fixture because I wanted to grow some things that required more light. I got a second one because I thought I would go for really high light, but then the hood went south, I had a whole lot of algae and I started getting sick (completely unrelated to the aquarium). I took the whole thing apart -- gave the fish to a LFS and dumped a humungo java fern that could have eaten Chicago.


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## cs_gardener (Apr 28, 2006)

I'd start with the 30 watts and then increase later as needed/wanted. That would give you enough light for the hardy plants to get your tank established but shouldn't create an algae farm.


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## Deni (Jul 6, 2005)

Thanks. That's what I'll do, then. I really appreciate the input. Sometimes I have the hardest time making up my mind.


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## hoppycalif (Apr 7, 2005)

I don't agree that a 10 gallon and larger tank can go by the "2 watts per gallon" "rule". In my experience a 10 gallon tank needs a lot more than that to have moderate lighting. So, I agree with those who recommend starting with 30 watts, minimum. I think you will be most satisfied if you have all of those lights available in the hood (is there room?), so you can turn on more if you find you need more.


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## Deni (Jul 6, 2005)

I can have two fixtures in the hood. So I can have the following permutations, with the fixtures I have:

1x15
2x15
1x15 + 2x15
2x15 + 2x15

Unfortunately, there isn't room for all three fixtures at once.


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## cs_gardener (Apr 28, 2006)

The 3rd option of 3x15 watt would give you more options of plants that you could grow. As I said the 2x15 would allow you to grow the hardiest low-light plants, but the 3x15 would give you the freedom to grow moderate light plants and that's what I'd choose. I don't know if the 4x15 would be helpful or encourage algae. I can see why you've had problems deciding.


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## Deni (Jul 6, 2005)

LOL Yes. Too many choices and a person who hates making decisions. (Don't ever ask me where we should go to eat. We'd both starve!)

I think what I'll do is to start with the 2x15, as you suggested and then add the 1x15. If I get something that doesn't seem to be thriving because of low light, I'll switch out the 1x15 for the other 2x15. 

I really appreciate all the input.


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## cs_gardener (Apr 28, 2006)

That sounds like a good plan. Do it now so you don't change your mind!


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