Treat star san water w/ campden?

My bottle of star san has a label from my LHBS that reads “do not mix with chlorine”. I have always used tap water and mixed at the proper ratio 1 oz to 5 gal (I do .5 oz to 2.5 gal, who needs 5 gallons of sanitizer?). I have never noticed any ill effects.
Should I treat the water with 1/4 tab of campden? I don’t know if it is necessary, I am just curious. I heard that distilled water will lead to a longer useful life from the sanitizer solution. Currently I keep a batch of sanitizer in a bucket for about a month. Any thoughts?

You’re fine.

When they say don’t mix with chlorine, I would imagine they mean “don’t dump it in your swimming pool.”

I figured the amount of chlorine in tap water is pretty small. I’m also curious if the presence of chlorine reduces the shelf life of mixed sanitizer solution ? I know minerals do.

I can’t speak to the shelf life, but I’ve had a gallon jug of sanitizer from tap water solution that I’ve been using for several months. Seem to work just fine. I haven’t checked the ph though, so I don’t know for sure.

I never thought to use distilled water. Next batch I might do just that. I also usually mix 2.5 gal batches then keep in a clean Home depot bucket. I replace every 2-3 months or 5-6 batches, maybe replacing more than I even need to.

I’ve always used tap water. My tap water is pretty soft, but it does contain plenty of chlorine. Never had an issue.

Household chlorine is a base, StarSan is an acid - they’re telling you to not add the StarSan concentrate to chlorine or risk getting both shot into your face when they react and release a ton of heat.