Chlorine Effectiveness

[Calisoldier83]

I was wondering how long chlorine should be present in the spa, when not in use? If I recently added chlorine and didn't use the tub for a day should it still be present in FC test under balanced conditions?

[The Wizard of Spas]

Too many variables to answer so far:  How much did you put in?  What type of chlorine is it?  What was the level prior to adding?  So on, so forth.

Additionally:  It depends on how often the tub gets used, how many people are in it and how long.  You tend to add your sanitizer after a use and the more consistent you are with your usage habits the more predictable your chemistry levels become. 

Are you going to be gone for a length of time or are you just asking in general?

[Calisoldier83]

Too many variables to answer so far:  How much did you put in?  What type of chlorine is it?  What was the level prior to adding?  So on, so forth.

Additionally:  It depends on how often the tub gets used, how many people are in it and how long.  You tend to add your sanitizer after a use and the more consistent you are with your usage habits the more predictable your chemistry levels become. 

Are you going to be gone for a length of time or are you just asking in general?

I added bleach yesterday and I'm not getting a chlorine reading today. I used bleach for the first time yesterday and I'm not getting a FC reading today. The bleach is over a year old, so maybe that's why. I'll go back to Dichlor today with a heavy dosage.

I was just curious how long I should be good if I don't use the Jacuzzi for a day or two at a time, if I'm sick or otherwise.

[The Wizard of Spas]

Full Disclosure:  I am not a proponent of bleach.  Others on this site are and I'll leave it to them to expound on the best practices for using that product.

Most liquid chlorines have a shelf life of only 90 days or so, and the more the bottle is jostled, the more gas is generated and released.  This lessens the effect of said product.  Additionally- Bleach burns off rather quickly.  Thus- You have two things working against you as it pertains to chlorine loss.  I'd say its one of these two factors that have caused your low chlorine readings.  Other things could be you put in too low of a dose, your testing equipment is bad or mis-fired, etc.

Di-Chlor is how I go if I do standard chlorine.  There is a very recent thread you should search for on this site pertaining to bleach / Di-Chlor and it may help better explain the pros and cons of each.  Regardless of what I think, the most important thing for you to do is to find a sanitation method that works for you and keeps your tub safe and clean, w/o damaging parts. 

I hope this helps.  Good luck moving forward.