mr_x is right. Providing even coverage is something worth looking into for under $100...
However, ,ith correct aquascape and tactical placement I'm sure one will get the job done and is getting it done.
They would grow more 360degrees with even lighting instead of reaching towards the one strip. This is why I supplement my LED
with 6xT5 24" though.. It's 4ft above my tank though. LEDs are 2.5ft above tank. 20gL ~30"/12"/12". This would be wayyyy too much light if not this high, but it provides full coverage and there's definitely benefits.
Two of the Kessils are angled downward to provide lighting underneath corals and prevent shading. This reduced PAR but I think I have enough coverage above.