JohnS_323 said:Wow Wendy, look what you started! Poor newcomer asks an innocent question and raises a sandstorm of controversy!
For your 75 with sump and fuge, do what you think looks right. You're going to have plenty of other filtration processes taking place, so the amount of sand YOU choose shouldn't be that big of a deal.
As for rock, same thing. On the surface, 100-120lbs sounds pretty good. It's all going to depend on how dense the rock is and how tightly packed you want your "reef" to look. The standard recommendation is 1.5 to 2 lbs per gallon.
I'm sorry for apparently opening a can of worms, I really am. :-[
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Wendy