I will repeat what I said earlier. Whenever we see someone who does not seem to dive like a dream, the immediate assumption is that there must have been poor instruction. It may well be poor experience after good instruction, including not doing a whole lot of diving over a period of time and/or doing a lot of diving with operators who do as much as possible for you, including setting up your gear for you, doing all the dive planning, and even taking your fins off at the ends of the dives. (Yes, I had that experience recently, and it certainly sped up the process of getting the group back on the boat.
You might be surprised at how easy it is to forget basic stuff with even a short time away. I once did a scuba refresher in a pool for a woman who had well over a hundred dives, all racked up on annual vacations. She was about to go on another one. She showed up with all her own gear, including a hose-mounted air-integrated computer. When she opened the tank valve and saw it read her tank pressure, she noted that it had also analyzed her gas at 32%. I told her that was not true, but she insisted her computer analyzed oxygen content, and she had 32% nitrox.
It took me a while to convince her. I told her the shop did not even have the ability to make nitrox unless I did it for them, and they certainly were not going to put it in the tanks supplied for a swimming pool refresher class, even if they could. This was a very intelligent, highly educated woman. She had in the past dived with 32% and set her computer for it, as she had been instructed, but in the time that followed, she had forgotten that part and assumed that every tank she had was being measured at 32%. It is possible that every tank she used did have 32%, but that would have been a matter of luck.
You might be surprised at how easy it is to forget basic stuff with even a short time away. I once did a scuba refresher in a pool for a woman who had well over a hundred dives, all racked up on annual vacations. She was about to go on another one. She showed up with all her own gear, including a hose-mounted air-integrated computer. When she opened the tank valve and saw it read her tank pressure, she noted that it had also analyzed her gas at 32%. I told her that was not true, but she insisted her computer analyzed oxygen content, and she had 32% nitrox.
It took me a while to convince her. I told her the shop did not even have the ability to make nitrox unless I did it for them, and they certainly were not going to put it in the tanks supplied for a swimming pool refresher class, even if they could. This was a very intelligent, highly educated woman. She had in the past dived with 32% and set her computer for it, as she had been instructed, but in the time that followed, she had forgotten that part and assumed that every tank she had was being measured at 32%. It is possible that every tank she used did have 32%, but that would have been a matter of luck.