Some hydro advise needed


Question from a fellow grower:

Currently, I have 2 plants set up as hydroponics and I have a 600 watt light set up. With my fan going the temp stays around 28 degrees Celsius. My plants are 2 weeks in since I got them as clones. Would it make much of a difference to bring in a 2nd 600 watt light if I could still maintain this temperature?