View Full Version : Question about t5 and t8 lighting
Anaxus
03-10-2003, 1:45 PM
I have a eclipse3 system. On marinelands website there online manual says the eclipse3 system uses 2 24" T8 20 watt bulbs. But on my eclipse the bulbs are listed as 24" T8 18 watts. Can they be interchanged?
Anaxus
03-10-2003, 2:06 PM
edit:made mistake in first post and fixed it
slipknottin
03-10-2003, 9:38 PM
Yes, they can be interchanged as far as the ballast is concerned. The real question is if you could fit a bulb thats 1 1/2" in the slots.
T8 bulbs will be 18 watts, T12 bulbs will be 20 watts.
The T12 bulbs are also less efficient and will result in less light output.
Anaxus
03-10-2003, 9:49 PM
I have seen some bulbs that are T8 that are 18w and some that are 20w same length. Would it matter which I use, aslong as it is a T8 and 24"?
slipknottin
03-10-2003, 9:57 PM
I have never heard of a 20 watt 24" T8 bulb, but maybe they do exist.
No it wouldnt matter. It sounds like more of a marketing gimick than a real wattage difference.
AntmanMike
03-10-2003, 9:58 PM
they dont exist.
Anaxus
03-10-2003, 10:15 PM
http://www.drsfostersmith.com/product/prod_Display.cfm?siteid=6&pCatId=3816
Hagen power-glo 24" T8 20 watts
also
http://www.drsfostersmith.com/product/prod_Display.cfm?siteid=6&pCatId=3812
Hagen Marine-Glo Fluorescent Tubes 24" T8 20 watts
http://www.hagen.com/usa/aquatic/product.cfm?CAT=1&SUBCAT=112&PROD_ID=01016260020101
Looks like all of hagen's 24" T8 bulbs are rated 20watts
Did they just mark them up from 18?
AntmanMike
03-11-2003, 3:45 PM
Probably. The T8 Specs state that 20 watt is just a standard bulb with T8 diameter.
Anaxus
03-11-2003, 6:40 PM
So the hagen bulbs would be fine?
AntmanMike
03-11-2003, 6:41 PM
from what I read, the Standard T8 DIAMETER bulbs do not work with T8 ballasts. They only work with standard ballasts. True T8 bulbs do though. 18 watt = T8, 20 watt = T8 DIAMETER.
slipknottin
03-11-2003, 6:42 PM
T8 ballasts will run both types of T8 bulbs as well as T12 bulbs.