new freshwater tank setup(newbie questions)

I just got a set of 3 90 gallon tanks yesterday and I am anxious to
set them up. I have been trying to do some research online since
I want them to be planted tanks. I have to buy everything so I want
to make sure and do it right. I am wondering if I should use Onyx or
Flourite sand in my tank. I have read that both are good although it
also said that after washing the flourite so it won't make your tank
cloudy you might as well be back to aquarium gravel. Is this true?
I am planning on using 4-6 4" T8 bulbs to light the tank depending
on what will actually fit inside the canopy. That would make 128-192
watts giving me about 1-2 watts/gal. I already have some crypt affinis
and some hornwort to put in it however I am looking for some
suggestions on what else to add that will fit well in the tank. I would
like
some type of ground cover tall enough so that fish fry can hide in it.
I don't plan on adding CO2 right away buy eventually I probably will.

Any suggestions are appreciated! TIA!

Peter

PD: I have read that both are good although it also said that after
washing the flourite so it won't make your tank
cloudy you might as well be back to aquarium gravel. Is this true?

I don't know where you heard this, but I can tell you this is not the
case. As far as which to use, Onyx or Flourite, it is up to you. Both
will be great for plants. The Flourite does contain higher iron
levels, but if you dose iron, this will not matter.