We have just bought a small spa pool, and would like to know the affects and side affects of all the chemicals we were given with it, are they really necessary. Our water has no chlorine.

H2 OK
Filter Cleaner
PH Decrease
PH Buffer
O2 Shock
PH Increase
SunPurity Mineral Spa Sanitizer.

So what I would like to know is: What do these chemicals do, are they really necessary, what are the side effects etc..

Thankyou