Make sure you wash the Pool filter sand VERY well to.
I just removed 300 lbs of Pool Filter sand from my 300g.
For one, I did not like the look. And two, even after washing
the crap out of it, it was still dirty.
So do it right the first time. Wash-Wash-Wash-Wash...And wash it again.
It's not fun trying to get that sand back out of your tank.