We found someting interesting that may or may not help those who are trying to get their EW to float. We use a condom to collect our sample and when DH would cut a hole in the end of the condom to get his 'sample' out(This was just a new thing for us as we were desperate to get more of a sample and cutting the whole seemed to work better than just pouring the sample out from the other end) but when we used the cut end to get the sample out we found that there were lots of tiny bubbles.
Everytime we had these little bubbles the EW sunk no matter what we did..... we then started thinking that the bubbles were probably mixing with the EW adding weight and sinking the EW. When we went back to pouring the sample out, there were no bubbles and the EW floated!!!
So to sum up our find...... if the sample has tiny bubbles across the top of the 'sample' this may be the reason that your EW is sinking....
I would love to hear if anyone else has these tiny bubbles....