How many tanks can you have for scuba diving?

Scuba diving oxygen tanks ?

• In a scuba tank where do they get the oxygen. I mean how do they I guess "make" the oxygen do they just fill it up with a special machine. If so what is it called?? Thankyou for the help (:

• Answer:

  In normal recreational scuba diving, the divers breathe air (21% oxygen, 79% nitrogen, trace % of other gases). The tanks are filled using a compressor that can deliver clean and dry air. The only special thing about the compressor is that it provides clean, dry breathable air. Using a "regular" compressor can introduce contaminants into the air which can become fatal/deadly/harmful at depth. With additional training, there is oxygen enriched air (aka nitrox). Oxygen enriched air has an oxygen percent between 21% up to 40% and the nitrogen is reduced by the same amount that the oxygen was increased. For example, you could have a mixture of 30% oxygen, 70% nitrogen, and trace % of other gases. Special training is needed to use these mixes safely. The compressor needs to be "oxygen clean" to be able to handle the increased fire risk in dealing with oxygen. With even further training, a diver can use mixtures with an oxygen percent above 40% and all the way up to 100% pure oxygen. Pure oxygen is used by some technical divers when they are doing decompression stops at very shallow depths. Special training is needed when dealing with oxygen greater than 21%. There is a chance of having oxygen toxicity. Oxygen toxicity can lead to convulsions. On land, the convulsions are not very dangerous. Underwater, the convulsions can lead to you spitting out your regulator and drowning.