T5 or LED?

[houiej]

My tank is 30x18x18 inches (2.5x1.5x1.5 feet) and holds about 40 gallons / 150 litres. Previously I read about the 2 watts per gallon guideline so that would mean getting a 80w T5 light.

How does it work if I want use LED light instead? How many lumens for a 40 gallon tank?

[sqwerc]

As far as I know the watt per gallon rule does not apply for LED. I think it really depends on the plants you intend to grow as well. From a user perspective LED runs longer and less heat is generated as compared to T5HO lights. Light spectrum is equally important for planted tanks. LED to the human eye can be brighter but due to the incorrect spectrum may not be useful for plant photosynthesis.

I'm no expert so do correct me if I'm wrong

[Urban Aquaria]

Yeah, the watt per gallon rule is a rather old fashioned guideline and doesn't really apply to LEDs as they are usually much more energy efficient compared to T5 lights.

From what i've experienced using T5 and LEDs so far, i guess as a very rough guide, you could probably be expecting half the wattage (or even less) when using LEDs.

For example, if you were considering 80W of T5, then 40W of LED would probably give the same or better results.

For lumens, the higher the better, but that mostly just indicates the brightness of the lights that we can see with our eyes... if you are going for plant growth, you'll also need check that the LEDs are designed and calibrated for plant growth, as in they are using the correct spectrum (not just color temperature).

Imho, the best way to know which LED lights are suitable is to see actual examples of tanks with the lights used on them.

Either you can read what LEDs others have successfully used on their planted tanks, or visit shops like East Ocean which have demo planted tanks with various brands of LED lights used on them, so you can see their performance and gauge their suitability for your tank setup.

[nickel]

In my opinion, light spectrum is a key parameter to be considered, besides the wattage. Brightness can be a misleading judgement based on human eyes and what plants really needfor good growth.

LED seemed to have more narrow spectrum compared to T5. I stand corrected on this in general.

[houiej]

Okay my tank is low tech. There will be no CO2, just regular dosing of Excel and Excel Flourish. Planted with undemanding plants. I'm leaning towards LED because it is energy saving and less heat produced. I just need a light that sustains the plants. Fast or thriving growth is not that important to me. In that case, can I just go for any brand or spectrum? What are some brands that you would recommend?

[AQMS]

If you want to have a go at the ready made led lighting, its gonna be expensive.
But in the other hand, if you know what kind of led you need to get and make the fixture yourself
you gonna save a lot more.For brand wise not so sure which is the best,spectrum wise
blue should have (400-490nm) the best is (465-485nm) for deep tank.Red is (630+nm).
Kelvin for freshwater aquarium plants 6500k.
If you want to have more info about lighting read this
http://www.americanaquariumproducts...._lighting.html

[Urban Aquaria]

Okay my tank is low tech. There will be no CO2, just regular dosing of Excel and Excel Flourish. Planted with undemanding plants. I'm leaning towards LED because it is energy saving and less heat produced. I just need a light that sustains the plants. Fast or thriving growth is not that important to me. In that case, can I just go for any brand or spectrum? What are some brands that you would recommend?

For your setup, i would recommend the Up Aqua Z-Series Pro LED lights... but then i noticed your tank is 2.5ft wide which is abit of an odd size, and the Z-Series lights only come in up to 2ft versions locally. Maybe you can check with East Ocean and see if they can help you order in the longer versions.

If they can't order the longer version in, then you could consider just ordering the 3ft version from eBay (the plastic side holders can be easily adjusted to fit your tank width), here is the eBay seller i ordered my sets from a while back:

http://www.ebay.com.sg/itm/34-6-LED-...-/271068493460

The main reason why i recommend this series of LED lights is because i have used them successfully in my tanks to grow HC, glosso, riccia, fissidens etc (the popular aquascaping carpet plants)... in addition they are priced well, very energy efficient and have a nice slim casing.

Alternatively, you could also consider the new Odyssea Evo LED lights from East Ocean, they use more powerful individual LEDs with lenses which help to get light further into deeper tanks:

http://www.aquaticquotient.com/forum...29-Plant-White

They cost more but are correspondingly more powerful... note that with higher light intensity, come higher algae growth too, especially in non CO2 injection tanks, so you have to really balance the lighting period carefully when using more powerful lights.