Hello, everyone! I'm a gardening newb, but have become hooked very quickly. After adding my plants to his app, I've discovered they may not be receiving the proper light. Most specifically I worry about these cacti (meet Louis and Gregory). I was going to place a grow light strip on the underside of the top shelf, but that will only help the cactus on the bottom shelf. What do you recommend? This shelf is pretty well anchored into the wall, and I would like to keep it if at all possible. Thanks in advance!