I also own the hop blocker and it's a complete waste of money in my opinion. It is hard to use, you have to open the lid and when hop blocker starts showing you have to pull up on the hop blocker to expose the finer "filter".
All I do now is do a whirlpool for about 5-10 minutes, then let the wort sit for another 15 minutes. Creates a great cone in the middle. I use a therminator, and have only had one blockage with it...and it was with the Hop blocker. Now I whirlpool only, no problems with the Therminator.