Flippin sweet dude!!
If it were me, i would ditch the t12 and get t5. They are waaaay more efficient and put off a ton more light. Plus i dont know of many sources for t12 reef lights.
You can buy the waterproof end caps...https://www.aquacave.com/t5-waterproof-socket-end-cap-1ct.html?fee=1&fep=709&gclid=Cj0KCQjw6eTtBRDdARIsANZWjYYclhjcoU06r60uKtQ52MIaEnf4kqYvYuEabrt-8oGQ2ehljM0M-uYaAkisEALw_wcB
Then pick up a t5ho ballasts. There are like $15 a pop. If that is 8 feet you are going to have to do double 4 foot on each side. Wiring is stupid easy. One pin red, the other black.