We have trouble getting ew to float. We have had 3 with succes and a lot without.
We then tried to just take some sugarwater and EW and wow that floated. Then we tried just water and it sank.
So if you havent tried it with succes then you can try with just sugarwater ( no semen ) just to see how it looks when it floats.
The best floating we have had is when we put at least half the amount of sugarwater in the semen and makes sure that there are no bubbles in the semen. Also the best succes in the incubator is when the temps is about 36 and not 37. If it goes to high it will be mix after 1 hour.