It is not too complicated, but it might be confusing...so try and follow me: if you have 2500iu of HCG and add 1cc of Bacwater then your concentration would be 2500iu per cc. If you wanted 250 out then you would need .1cc of the mixture....far too small an amount to be accurately measured in your syringe. If you add 2cc if water, your concentration would be 1250iu per cc, and you would draw .2cc for 250. Again, far to small an amount to dose properly with a typical syringe. If your HCG bottle is large enuf, add 5cc of water, and draw 1/2 a cc for 250 out dose.