Bifen IT is mixed at 1oz per gallon of water. Each gallon of finished solution will cover about 1k sq ft.
We have not heard any feedback on Bifen IT becoming gel-like when mixed as directed on the label. Make sure you are shaking the concentrate well before tank mixing, and agitate thoroughly before and during applications to ensure that the mixture has gone into solution. You can also contact the manufacturer Control Solutions for additional support by visiting their website's contact page here.