When to take the final gravity?

[cafelinhchi]

So ive just bottled my first batch, ever.

When I took the sample for my F.G., I took it before bottling anything and i got a 1.020. But after some time i notcied that there was a tremendous amount of sediment at the bottom, so i decided to take another sample. The second sample was much, much clearer and I got a reading of 1.0015'ish.

So now I'm understandably confused. Its a big differance in ABV.

So can anyone clearify this inigma for me?

[Guru]

How much time between the 1.020 sample and the 1.0015 sample? Was there a temperature change in the beer during this time? Also what sort of beer are we talking about? Hard to tell whats going on without a little more information.