convert t12 to t8

Hello,
Lighting is my weakness so I need some help, the Petland guy said that I could switch my t12 to t8's using the same ballast. He claims that the prongs are the same distance apart and it would be an easy switch.
What do you think?

 

what kind of ballast is it? most ballasts are able to be wired in different configurations for a variety of bulbs, others are not.

example, the fulham workhorse 5 can power T5, T8, T10, T12 and in varied wattages dependant on the wiring. http://www.fulham.com:8080/Reseller/Products/Python_Scripts/select_FILE_py?FILE_ID=1053

 

The Petland guy is right regarding the interchangability of the two bulbs. The number following the T designates the number of 1/8ths of an inch. So, T12 is 1 1/2" in diameter, the T8 is 1" in diameter. The prong/pin configuration is the same. The difference is the efficiency of each bulb. For each watt, a certain amount of lumens is produced. The T8 is more efficient than the T12, it will give about 80% efficiency per watt. A T12 will yield anywhere from 40 to about 70% efficiency.

You should note that although T12 and T8's will light up a FOWLR, neither bulb is up to the task for a tank containing corals. The T5 is considered absolute minimum nowadays, they're a step above the power compact. The T5 however, will not fit in a fixture designed to house a T8 bulb.

Hope that helps.

 

I would suggest purchasing a T5HO unit instead of converting your bulbs to your ballast.