Is it bad to bring FC levels to just under shock levels each time you add chlorine in order to reduce the frequency of chlorine additions? For instance, I have my spa at a CYA of 60. By bringing it up to FC of 20 ppm (shock is 24ppm), I can get 6-7 days before it creeps down to the minimum of 5ppm.
Can't I just repeat this cycle over and over so I wouldn't have to test as often (I start testing on day 4) nor add chlorine as often? The only disadvantages I can think of is that it probably uses more bleach and there may be a risk to equipment, but it is under shock levels.
but it is very convenient.