How much light is too much?

[Stefanie]

I have been looking into upgrading the light on my 20 G tank, and I came across three options: One is a 65W PC fixture, one is a 110W (2*55W), and the thrid one a 2*65W PC fixture. Now 130W on a 20 G tank seems like a lot to me... is this overkill and 65W sufficient, even for some higher light demanding plants, or should I go for 110W or even the 130W?
I believe the 110 and 130W are intended for saltwater tanks, and thus come with a blue bulb. As far as I understand it can be replaced by a regular bulb, though?
I know that with higher light I will have to start injecting CO2, and I am finally willing to take the plunge and will start threads with a ton of questions when the time comes.

I am a total newbie so any advice is greatly appreciated!

I would like to take this opportunity to thank everyone that has helped me in the past. You guys are great and made me and my fish a lot happier!

 

[RTR]

If you plan on high-tech (pressurized gas and frequent fertilization and water changes), 3-4 W/gallon is fine. To go higher without already being experienced with aqautic plants is asking for trouble. If you want low tech, stick to 1 1/2-2 1/2 W/gal.

 

[Stefanie]

Thank you, RTR. If I understand you correctly, I should stick to maybe 1 55W bulb? This would give me about 2.5 wpg. I would like to do DIY CO2, so no pressurized system. Does this sound OK? Also, what plants could I grow in this light? Low and Medium light demanding? I never quite understood how the nomenclature works... what is considered low, low-medium, ...?
Thank you, again!

 

[djlen]

I agree with RTR on the wattage for a newbie.
Try to think ahead and imagine what you anticipate having down the road. Do you expect to get into more light-needy, higher maintenance type plants like reds for instance? And do you see yourself spending more time and effort as your knowledge increases?
If so you can buy the 1x55 now and pick up another one later if needed. I would not go over 2.5 wpg until you learn how to manage more wattage.
As to the bulbs themselves. I don't think you can go wrong tubes in the 65 - 6700K range. IMO, they give a very natural, eye-pleasing look.

Len

 

[RTR]

All the rules of thimb were devised for normal output (NO) fluorescents, PCs are more efficient so put out more light for the same wattage. Plus if you have a really good reflector (such as AHSupply's Miro reflectors) you get more light to the plants from that as well. So with PCs, the old standards do not apply as well as they used to do. Also PCs are a bit more stable in output than NOs.

To me 2.5 is the border between moderate and high light. Beyond that I need more ferts and a carbon source, below that I may not need much. But from at least 2 and up, I do better with added CO2/carbon.

Agree w/Len on the color temperature.

 

[Stefanie]

Thank you for your input. I decided to go with the following:

http://www.aquatraders.com/index.asp?PageAction=VIEWPROD&ProdID=23

I will only be using one of the 55W bulbs for the start, but at least I have the option for later to get even higher.

Do you know anything about the brand or could recommed something better if this one is not good?

I will also attempt to do a DIY CO2, but I will surely ask for more help, as this project progresses.

I am willing to add fertilizers and do frequent water changes, too. What do you consider frequent? My current schedule is twice weekly 50%. Will that be sufficient?

Sorry for all the questions, I just want to do it right and not have a desaster waiting...

Thank you again!