[flexkong]

currently I'm using FL light on my tank. Now wish to change it to PL light, so could I use the 40w FL e-ballast on 36w PL light?

 

[gnatster]

PL = Compact Florescent?

A definite maybe, it all comes down to who made the ballast and was it designed to run multiple type of bulbs. Some Workhorse brand ballasts can run straight Normal Output Florescent as well as Compact Florescent. Best to check on the ballast for an ID and then look the specs up.