I use bromine to sanitize my spa. How often should I test and shock the water?

I use bromine to sanitize my spa. How often should I test and shock the water? 

Spas are operated at high temperatures; experience heavy bather loads, and have increased evaporation due to aeration and circulation. What this means it that testing your spa water is very critical. Your spa water should be tested, at the very least, every other day to maintain adequate sanitizer levels and proper pH and total alkalinity levels. Bring a sample of spa water into Swim Rite Pools every 4-6 six weeks to have a complete water analysis done.

You should shock a spa sanitized with bromine after every use. Shock should be added immediately after exiting your spa to oxidize and eliminate organic contaminants introduced by bathers. It activates the bromide which is the active sanitizer that is killing the microorganisms in the water. If you are not adding shock to your spa, you do not have a working sanitizer in the water keeping you safe from bacteria.