If there are 3-4 people in a 400 gallon hot tub for an extended amount of time, is it safe to add 1-2 oz of 12.5% bleach in the middle of the tub with jets on OR would you recommend people get out briefly? I"m in MN so getting out for a bit can be challenging for some when it's cold. I was getting snowed on in my tub this morning.