Hi Relle,
Yep, espeicially with the Crystal Clear ones. Are you using the in stream ones? I found also that using the in stream ones as dip sticks got the best results, I found that really early, there wasn't enough HCG 'in stream' . so I would collect FMU and then dip the in stream bit in and swirl around a bit....

It says on the box that this is fine, and you should 'swirl' for 20 secs

Can you post a pic of your results?

Good Luck