dsb clarification
 

i would go 3 inch, rocks can sink down into the sand so that you dont
lose any cieling room for taller rocks, and a 3 inch DSB in a 45 gal
would be alot more of a beneficial bio load than can be achieved with
a 2inch, and 1 inch is almost useless and WILL get disturbed as your
LFS says, having it deeper allow for better stratifying of the layers
eliminating this problem, and is important to keeping your rock
healthy. if you had a 80 gallon or greated i would go 4-6 inch. you
can push back the front of the DSB to expose a bit more of the glass
as everyone has mentioned only seeing about 2 inches in the front if
that helps, but personally i liek a Deep sand bed, i have a 2.75 inch
in my 29 gal pod.