I want to start using clorox in my hot tub this fall.. I only run it in the winter months and then only use it about once maybe twice a week.. how much clorox should I use per gallon and how often does it need to be added? thanks!

Hi and welcome fellow newbie. Please have a read here: http://www.thepoolcalculator.com/

Welcome to TFP!

How to User Chlorine in your Tub or Spa is a great place to start.

As previously mentioned Dichlor/Bleach is the method to use. I sanitize my tub with this method for about $2 a month.

A must have to properly use this method is A GOOD test kit like the Taylor K-2006 or TF-100. What you spend on the kit will be recouped in chemical savings within the first year.

Be sure to use Dichlor initially to build up the CYA level (around a week or two) and then switch over to using bleach. You want to add enough chlorine after your soak such that you measure around 1-2 ppm FC just before your next soak. If you do not have an ozonator, then roughly speaking every person-hour of soaking in a hot (104ºF) tub will require 3-1/2 teaspoons of Dichlor or 5 fluid ounces of 6% bleach or 7 teaspoons of non-chlorine shock (43% MPS) to oxidize your bather waste (the non-chlorine shock would only be for Nature2 systems or for bromine spas). If you have an ozonator, then the amount of chlorine you will need will be higher if you use the tub less frequently (say, once a week) or lower if you use it more frequently (say, every day or two). Your twice a week usage is in-between so it's hard to predict what would happen if you have an ozonator. Read the link Jason referred to. Getting the Total Alkalinity (TA) lower and using 50 ppm Borates are important in order to have stable pH.

I read most of "How to User Chlorine in your Tub or Spa"..then my eyes started bleeding and my mind started wandering.. I got to the part about "if you cant test every day find another method".. and I quit.. well I probably cant test every day.. a lot of the weekends we are away from home.. so.. can you all suggest a really simple method I can use? thanks!!

In practice with some experience of your own a routine will be established. You will test alot the first month while you learn what your tubs needs are. I know my routine and only test once a week.

It's not a problem to leave for the weekend with chlorine. I left out of town this Friday to return Sunday to a tub with a FC of 3 ppm. Just bring the FC up before you leave. In general with no organic load a tub will loose 25% fC a day so it can be left alone for a few days.

You can try Bromine. For me it was more work than Dichlor/Bleach but different people like different sanitizers to suit their situation. Dichlor/Bleach is cheap enough to warant a try IMHO.

Could one use the proper dosage of granulated CYA in lieu of Dichlor and begin using bleach to chlorinate immediately?

I have tried this once and overshot my goal by a bit. It's difficult to know exactly how huch water is in your tub. By keeping track of FC with a good test kit you will know how much CYA is exactly in your tub.

If you are going to be away from the tub a lot (not just a weekend, but for an entire week or if you don't want to do anything during mid-week), then bromine tabs in a feeder (along with an initial bromide bank) might be a better bet for you. Read Using Bromine In a Spa and see if that suits you better. As was noted above, some people like one approach better than the other.

Note that if you aren't using the tub a lot (i.e. not every day or two), then chlorine works better when there is no ozonator. In a spa with an ozonator that gets infrequent use, you end up using more chlorine since ozone reacts with chlorine. Tubs with ozonators tend to work better with bromine as the ozone creates more bromine from an initial bromide bank.