I havew a fairly new CLX450 that came with the low profile dump valve. After 12 dives with the suit, I contacted my LDS with the two complaints addressed in this thread (slow venting, leaking). I requested a replacement high profile valve and DUI sent out the new valve without argument. The only excuse DUI had for the leaking low profile valve was that not enough air was kept in the suit to keep water out. I just had the new valve installed and hopefully will be in the water this week to check it out. If you are haveing problems with the low profile valve, let DUI know about it and get it fixed under waranty. Maybe if enough owners complain about the poor performance of the low profile Apeks valve, DUI will find a better alternative for their otherwise outstanding dry suits.