Unless you have an ozonator, which would inject ozone (O3) to sanitize, there are no gases added to the water of a swimming pool.
Usually gas or heatpump
Oil, natural gas, and propane
You use a water heater, which may be electric or gas, to circulate the pool water through and maintain temperature.
Chlorine?<3
Many people are choosing to remodel their swimming pool systems to add saltwater chlorination. With a saltwater pool system, a chlorine generator is added to the pool's filtration system. The water circulates through the chlorinator, where salt produces a chlorine gas that dissolves into the water. That chlorine in turn, breaks down and turns into salt, cycling the process all over again.
b/c you're less dense than the water (likely due to the gas in your lungs).
A salt water swimming pool is a pool that has had salt added to it in order to be able to use the salt in water that is circulated through the filtration system and run it through a chlorinator. This is a set of elements that electronically create chlorine gas that is almost instantly dissolved into the water to sanitise it. The concentration of salt in the water is about 1/8 that of sea water or about the same as that in tears.
A salt water pool is a chlorine pool. The difference is that in a normal fresh water pool you have to add the chlorine as it is required. In the case of the salt water pool salt is added to the pool which is int urn run through a chlorine generator that is installed on the pipe leading from the filter to the pool. The chlorine generator electronically separates chlorine gas out of the salt water which then dissolves into the water automatically maintaining chlorine levels. The adidion of salt to the water makes it more pleasant to swim in and you are spared having to handle and store chlorine at home. but the problem is you are still swimming in Chlorine and now you are also swimming in sodium.
Yes you can retrofit a salt water pool system onto your existing pool equipment without too much trouble.
A pale green gass which is called chlorine is used in water for purification. and clean pool water by bicterias tha can be hazardous to humans
Chlorine itself is rarely used as a disinfectant in swimming pools; generally are used other chemicals as sodium hypochlorite (NaClO), etc. Dissolved in water sodium hypochlorite release chlorine; and consequently gaseous chlorine exist as a solute in water.
With a thermostatically controlled gas heater. Solar heaters are also used for pools.