Well, that's 45 gal of water at 8.3 lbs per gallon, about 373.5 lbs, plus about 15 pounds of salt in the water, plus the LR and LS about 65 pounds, and the weight of the tanks, about 40 pounds. That's a total of almost 500 lbs.
The bottom line is that I wouldn't trust that kind of weight to a TV stand no matter how nice it was. I would not even consider reinforcing a TV stand because many are made of of particle board which is not going to do well once it gets wet. Even if it's made of of other materials it only takes one failure to create a massive mess to clean up.
Either get yourself a for real aquarium stand or build one. You'll sleep much better at night. Building a stand is not too difficult, and because you can over engineer the stand, there is little risk of it failing.