Steve,
You said you were taking diving lessons. Did you show your setup to your instructor?
Personally I think you are taking a risk that just doesn't need to be taken. NO GOLD is WORTH A LIFE.
Putting the hookah hose on a snorkel is so stupid on so many levels it isn't funny. Even with a regulator you are buying you now need to figure out what connections you will have to put on the hookah hose to attach the regulator. Also scuba regulators are set to handle 300psi pressure. I am positive your hookah will not put out 300psi's of air. So are you getting a hookah second stage regulator?
Do you have a wet suit. Being underwater in even warmer water for a long time will get you cold. Do you have weights? Do you know how to clear a mask if your mask strap breaks? Do you know how to clear it underwater if it floods?
WHY risk your life for a lousy bunch of gold? What will you do if your compressor stops dead? Will you have enough air to come up?
They make QUALITY hookah's for a reason. So you can DIVE SAFELY. I told you and others my opinion. I am done trying to reason with your decisions.
I will congratulate you when and if you find some finds with it but will not bring up my concerns again. WATER KILLS. One of my best friends and two acquaintances have died while detecting and WADING.
Diving is DANGEROUS. Sure people do it all the time. This is not an attack, it is a major concern for ANYBODY wanting to dive for deeper gold. I am not trying to do anything but help. If I come across strong I apologize. I just want people to stay safe and love life.