I just got a a 75 galloon tank and was trying to make the decision on which way to go on substrate. I went to my local pool supply store and they were closed so I went to Lowes and got play sand washed it according to the directions posted (for hours) and put it in my tank. The image was taken shortly after I was done.
On day 2 - it was still very cloudy. Changed all the water and it was still cloudy altho not as much.
on day 3 - it looked the same and didn't want to spend a fortune on water changes so I gave up. I vac'ed all the sand out and went back to the pool supply store to get pool filter sand.
Play sand - $7, Pool filter sand - $20. Having a clear tank as soon as I put in the PFS..... PRICELESS!
The washing process took half the time and the water is clear. I wanted to post this so if anyone else was making a decision on substrate they would have images of what it looked like for me.
EDIT: Both images were taken within a hr of putting in the water....