T8 to LED output conversion

**uklau** · 11th Aug 2014, 22:34

Hi folks,

I would like to seek for some quick help on this area. I used to have a tank approx. 2x1x1 running on 2 18W T8 tubes. How does that translate to an LED source (how many W) for 23cm x 23cm x 30cm (H)?

Thank you in advance.

**Urban Aquaria** · 12th Aug 2014, 11:24

For your tank height and size, you would probably be looking at a narrow clip-on LED light model that runs on around 10-15W range (actual intensity required depends on types of plants and whether you'll be injecting Co2 + ferts), preferably with 0.5W or higher individual LEDs (make sure they are designed with spectrums for growing plants).

**uklau** · 13th Aug 2014, 21:56

Thanks, bro. Probably I'll set up a Diana Walstad "tank" with this free tank from a fellow former & get a 2 feet tank with LED lighting.

BTW, is 1W T5/T8 translates to 1W in the LED world?

**AQMS** · 14th Aug 2014, 08:50

Originally Posted by uklau

BTW, is 1W T5/T8 translates to 1W in the LED world?

No it does not work that way.Here are information on lighting that will help you with your lighting setup.
http://www.americanaquariumproducts...._lighting.html

**Urban Aquaria** · 14th Aug 2014, 17:14

Originally Posted by uklau

BTW, is 1W T5/T8 translates to 1W in the LED world?

So far i haven't read on any direct comparisons dealing with wattage between T5/T8 light vs LED and their effects on plant growth.

But from my own personal experience (not scientific, just based on having used both T5 and LEDs on my own planted tanks), i find that its sort of a 2:1 ratio.... as in i get the same or similar plant growth with LED lights that run on around half the wattage of T5 lights.

So if i used to use 36W of T5 lights, i still get same plant growth rate when i switched to 18W of LED lights. That being said, the spectrum/intensity of the individual LEDs and their layout also affects the overall performance too (ie. wider spaced arrays for larger tank base areas, higher powered individual LEDs for deeper tanks), so there are many other variables in effect.

Note that T5/T8 lights will usually appear to look brighter compared to LED lights when used on aquariums... one of the reasons is because T5/T8 lights emit their light in all directions, so half of the light shines up which then have to be re-directed down by reflectors in their casing, this creates alot more light scattering out and illuminating the surrounding area (instead of inside the tank) and this naturally makes it look brighter to our eyes. On the other hand, LED lights have a more directional light which mainly shines downwards, so more of the light is focused into the tank itself and less scatter out to the surrounding, hence they'll tend to look less bright to our eyes.