I also did some research on the Purigen and found that some folks do think that it slowed the cycle down. Most questions were based on why would someone be using the Purigen during a fishless cycle? Its ok if your water is a little cloudy when starting the cycle ie: bacteria bloom and all.
No need to worry about the water clarity at this point and you will be doing a good
water change once your tank cycles and then if you choose, you can use the purigen then.
I also read that you should not use the purigen if using any type of water condition that has the added slime coat additive as it will foul up the purigen beads.
I think that sticking with Prime when you have cycled your tank is the way to go, but thats just me. For now you do not need any water conditioner at this point in a fishless cycle.
Best of luck!
