greetings... a few opinions needed

Just wondering about some things...
(1.) anyone here about adding lemon juice to your water to help the ph?
(2.) anyone try using uv lighting from reptile lights?(pet stores- reflector 12 bucks, light 8...) the fixtures support up to 250 watts...
(3.) If you were 3 weeks into flowering, on a first time grow, would you consider triming small under branches to mack out top flowering? The plants in question are 3 ft and not that bushy... mostly top growth, I topped them 2x and flowered... sorry no pics this sec...and the only reason I would consider this is my light set up blows but the tops are hairy as hell...