[ganjero]

other than the wattage and lenght, is there a difference between 54w and 80w t5s?

 

[Wasserpest]

Both share the bulb diameter and connecting pins, everything else is different! :icon_wink

 

[ganjero]

what about efficiency, having the same total wattage output, is one better than the other ?

 

[bharada]

what about efficiency, having the same total wattage output is one better than the other ?

A 54w HO T5 is for 4' fixtures while the 80w HO T5 is for 5' fixtures. Like Wasserpest said, only the tube diameter and pins are the same. Length and wattage are different. You'd have to measure the actual light output for each bulb to determine which is more efficient with a particular ballast.

 

[Wasserpest]

what about efficiency, having the same total wattage output, is one better than the other ?

Not sure what you mean by that... One uses ~54W, the other ~80W, that is not the same.

Also, you need to define "better".

4ft bulbs are cheaper and there is a much better selection available.
5ft bulbs are maybe a bit more efficient, and you get the same light output with less bulbs (and connectors and reflectors etc)

Which one is "better"? You decide! :icon_bigg

 

[Betowess]

Where you save on the 60" is having more watts for same number of ballast. BUT, way fewer bulb choices. I've researched that in the past... I'd go 4 foot if it works with the tank.

 

[Wasserpest]

Where you save on the 60" is having more watts for same number of ballast.

I have to disagree with you here... I know it is splitting hairs, but say you have a WH7 ballast which can push up to 220W. You can connect 4 54W bulbs to it (216W) or 2 80W bulbs (160W). Quite a difference.

 

[crazy loaches]

Man I bet its hard trying to get a 5' bulb in the mail. So far almost every 4' bulb I have recieved has been broken in shipping, i'm 1 for 5.