I HAVN'T TURNED ON MY HOT TUB SINCE LAST NOVEMBER SOTODAY WAS THE CLEANING AND GETTING READY FOR MEMORIAL DAY SO I CLEANED IT OUT ADDED SOME WATER AND WHEN I TURNED ON THE BLOWER IT ACTS AS IF IT IS WORKING AT HALF STRENGTH. TYPICALLY WHEN THIS HAPPENED BEFORE THERE WAS AN AIR LOCK SO I WOULD DRAIN SOME WATER FROM THE FILTER WHILE THE JETS WERE ON AND THAT WOULD DO THE TRICK. THIS TIME NO SUCH LUCK, MY TUB HAS AN AIR BUTTON ON THE SURFACE OF THE TUB SO AS YOU UNWIND IT AND MORE AIR GETS IN THE JETS GET STRONGER. NOW UNSCREWING THE AIR BUTTON HAS NO IMPACT. I BLOW INTO THE AIR HOLE AND IT DOESN'T SEEM TO BE BLOCKED BY ANYTHING BECAUSE MY BLOWING INTO THE AIR INLET GETS AN IMMEDIATE RESPONSE OF MORE IMPACT ON THE AIR FLOW. DO YOU HAVE ANY IDEAS

Try lowering the water level an inch or two. If I understand you correctly, you are talking about the free flow air that works only when the jets are pumping air, from the vacume they creat as the water passes the orfice of the jet. I have found that if I have water all the way up to the brim, my lower jets do not create enough vacume at that depth to function. Do you have a forced air system in your tub?