water lettuce loves high light intensity, but lower temps (like that hasn't been said ten times already).
For Metal halide pndants it will be fine (so long as the light is far enough away not to fry it).
For guppy fry I like java moss on the bottom of a bare glass tank, or growing some sort of hairgrass, microsword, or hornwort for the fry to hide in. Anacharis is good too, but all my fry like to hide near the bottom, and anacharis does best when floating (for me anyway)