Toxxn

I noticed Tekkit does not have Optifine unlike some of the other mods in the Technic launcher. I know Optifine is updated as to I use it in my main game. Is there any way to manually add to Tekkit? Any help would be appreciated. Edit: I may have made a mistake by trying to install Optifine 1.5.2 previously instead of 1.5.1. I will update this in case this is the problem.