Different types of chlorine and which one to use (granules vs tabs vs liquid)
There are different types of chlorine that you can use to sanitize your pool. Liquid chlorine, granular chlorine or tablet chlorine. Salt Chlorine Generators are also available. No one method is better than the other, it really depends on your preference.
Liquid chlorine is completely soluble in water, it is a clean, pure product; and leaves no residue in pool water. It is an un-stabilized form of chlorine, which means that it will burn off quickly in the heat of the season if no CYA is present. Should be added anytime the Free Chlorine residual is under 2ppm.
The advantages to using a tablet form of chlorine is convenience. Tablets are slow dissolving; good for chlorinators and convenient to use. You can fill a tablet chlorinator and it will disperse chlorine daily. The disadvantage is the tablets are blended with CYA which is left behind once chlorine is used up. So, one season of tablet chlorine use, puts your CYA level above the recommended acceptable range. If you have a high CYA problem, then it would be best to avoid this method.
Some choose a granular form of chlorine which gets added daily. Not widely used, these days, as this would be a daily treatment to ensure proper chlorine level each day. Like tablet chlorine, granular also is blended with CYA and will quickly put your CYA level above the recommended acceptable range.
Liquid Chlorine is recommended for pools with CYA over 80ppm.