Lighting

[Mercury]

It seems that watts per gallon is the most common way people judge the lighting of a tank. What would be the WPG for these levels of light?

Very low, low, medium, high, very high

[TabMorte]

I think it's very subjective.

To me Low would be one or less WPG
Medium would be over one but less then three
High to me is over 3

That said it depends a lot also on the dimentions of your tank. I have yet to meet a plant I can't grow in my 10G by just plunking it down cause it's so shallow everything gets so much of the lightly. Where as on my 30 which is so much deeper I really have to think about where everything goes because the plants are further from the light and tall enough that the larger ones shade the smaller ones.

[ishar]

I would say each level of brightness you have listed would be 1WPG

Very low <1wpg
1 < low < 2
2 < medium < 3
3 < high < 4
4 < very high < 5

Generally you want to be within the 3-4 WPG range I believe, as this will grow most plants but won't be so much as to stress the plants or be overkill for nutrient uptake.

[Orion]

The WPG 'rule' is really a loose guideline to judge approximately how much light your going to need over a tank to reach a certain level. If you were to go 4 WPG on a 100 gallon tank, even with the best Co2 and ferts, your most likely going to burn out the plants. This is because the WPG rule breaks down for larger tanks, and for very small tanks.

Tab hit it on the head, it is very subjective. And the levels of light all depend on the types of plants you want to grow. I have 1.06 WPG over my 75 gallon, but all my crypts, ferns and anubias grow wonderful.

[Avalon]

In this day in age, the very old WPG rule is no longer an effective measuring stick to judge light adequate quantity. With so many lighting choices and much more advanced reflector technology, every situation is different. Add CO2 to the mix and you can effectively & significantly increase the effectiveness of your existing lighting per say. A simple flow chart would look like this (from least to most):

T12 --> T8 --> T5 --> PC --> T5HO --> MH --> HQI

Reflector quality can make a huge difference. Quality reflectors on T12's will result in plenty of light to grow most plants in many situations. Halides are typically far too strong for a planted tank and are only used in short bursts. Personally, I don't understand why you would want to bother with them. They look cool...for the very short amount of time you can run them.

[prgwin00]

I have a lighting question. I have a 55gal tank and a long tube florescent bulb lighted hood. At this time, I am not sure of the wattage as the writing has either faded off, or the bulb is turned where it can't be seen. Will this type of lighting be sufficient if it is the appropriate wattage? And what wattage will be needed for such a deep tank?

[TabMorte]

What kind of plants do you want to grow is probably the more appropriate question? Because appropriate lighting depends hugely on that. Also on what kind of fish.

[quote Generally you want to be within the 3-4 WPG range I believe, as this will grow most plants but won't be so much as to stress the plants or be overkill for nutrient uptake. [/quote]

I had to down grade my 4 WPG tank because it was stressing my fish out being under glaringly bright lights all the time :P I knocked it down to 2WP and they're all much happier.

[Avalon]

Originally Posted by prgwin00

I have a lighting question. I have a 55gal tank and a long tube florescent bulb lighted hood. At this time, I am not sure of the wattage as the writing has either faded off, or the bulb is turned where it can't be seen. Will this type of lighting be sufficient if it is the appropriate wattage? And what wattage will be needed for such a deep tank?

If it's a fixture that came with the tank, or one that has no reflector, it won't work. Plants really don't need a lot of light, but they need a moderately intense, evenly distributed source of light. By intense I mean light that can penetrate to the bottom of the tank well. Power compact lighting, along with T5 lighting will easily allow for this and good reflectors make it possible. The older flourescent lighting (T12 & T8) runs into problems such as dramatic loss of intensity over a short period of time (changing bulbs every 6 months to a year is just absurd). There are many options available. Using PC and T5's, I'd shoot for around 2 wpg. You can grow anything in a 55g with 2 65w PC bulbs with good reflectors (AH supply). That would probably be ideal for either non-CO2 or CO2 injected tanks. CO2 boosts growth rates substantially without adding any more light. Moderate lighting will also help keep you out of major algae problems.