Although chlorine is a poisonous gas which can kill people, and chlorine was used for that purpose in WW I, it is virtually impossible that your hot tub will contain so much chlorine as to endanger your health. It's safe.
To little and bacteria can thrive, to much and it can be harmful to the body.
It is safe. That just means that the chlorine is not actively killing bacteria. It would be unsafe if there was too much chlorine.
Be careful when testing for chlorine. No chlorine will have a clear reading but too much chlorine will cause bleaching of the test reagent confusing you to think you have no chlorine in the pool, try doing a dilution test where you dilute half pool water and half tap water, If coloured results appear with dilution you know you have too much chlorine. Swimming with too much chlorine can cause skin rashes irritations, discolouring of swim wear rotting the stitches, and blacken jewellry.
It depends entirely on the concentration of the chlorine. If it's too strong, it can cause severe burns on the skin.
yes your skin could burn you should make sure that you put as much as directed no less or not clean and not too much or too dangerous
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People putting it in.
Only if there's too much of it.
Just let it disipate.
you die
yes if there is too much fire it can get too hot
In small amounts it is not, for example there is chlorine in pools to keep it clean but there is only a small amount. Too much chlorine is dangerouse for humans.