I will find out tomorrow for sure. they were doing it for free at the gym i goto (its a major college's rec center) and the professors were teaching the PHD students how to do it and the prof said he would let me go in the water tank tomorrow b/c he said i was the lowest he saw all day, he said the lower you are the harder it is to get an accurate measurement so I would be a good "subject" for his class tomorrow. I am going to be shocked if I am really 7%, i don't feel like it.
I've had the hydrostatic method done before and came back at 22%! At the time I know for a fact I was below 10% - about 5% according to the 9-point caliper method and about 7% according to Milos, who looked at my pics and was helping me diet down at the time.
He said that the hydro method can be very inaccurate as well if not done EXACTLY right. It's possible I did not exhale enough, which would lower my sumerged weight and increase my bf reading. He also said Ronnie Coleman once tested negative which is impossible. Milos himself tested at 25% just before a contest.
My point is, all of these methods can be very wrong. Now, I just use the 9-point caliper method and even though it may say 5% I don't care...
What matters is each week's relative reading as long as they are off to the same +/- % (which in my case they are). If so, I can guage progress regardless of the reading.