diy lights

I'm hoping one of the resident DIY lighting geniuses can help me with this - If it is possible. I have 4 aquarium hoods, one for a 36 gal bowfront (from Petsmart) and 2 10 gal (walmart) and a 5 gal (I think Petsmart) They all have cheap white LEDs, I'd love to know if it is possible to replace...