That looks like a rather tough tank to light well. For high light you're looking at getting a PAR of at least 80 at the substrate but one that also provides a pretty broad area since you do have a wide tank. Due to the width of the tank I would suggest going with two fixtures. 24" is a lot of space to cover and that would mean keeping a very powerful fixture pretty high above the tank. A pair of BuildmyLED fixtures would be amazing and would give you the necessary light but that would also be rather expensive. One option that I've been toying with is a DIY lighting fixture using PAR38 bulbs. It's very easy to build and you can mount the lights wherever needed in order to better cover the entire tank. There are some that are specifically made as "grow" lights that will hit the red side of the spectrum and that would help. Of course there are also your regular white ones that would be mixed in.