Ozone generators are very effective. Right speaking, they provide 60-90% of the sanitation a pool needs. Every pool still needs chlorination source for that reason, and because ozone does not provide "residual" protection (it doesn't continue to sanitize the water when the equipment is off). So since you need chlorination, in this day and age you can continue to do it the old-fashioned way with expensive chlorine or use a salt chlorine generator to take care of everything for you at a fraction of cost.