55 hood

[fishorama]

T-12 fixtures usually can take T-8 bulbs & there are more spectrum options in T-8. 5000k-10000k can work but some are better for fish & plant looks, I like 6500k, yellowish to some people.

That said, there several plants that can grow well under either: most crypts, swords, ferns, anubias, mosses...but only a few stem plants & not many "ground covers".

What do you want to grow? Or is more what can you grow?

 

[FreshyFresh]

T8s won't work in a T12 fixture unless it's got a ballast that will support both. You can try T8 lamps in a T12, they'll click into the 'sockets', but they typically won't fire up properly.