Dichlor

[Bigralphy]

How much dichlor is typical in a 1300 liter tub?  I seem to be using about 2 or 3 teaspoons a day.  There is only the wife and I in the tub and we don't wear perfumes or colognes at all but don't shower prior to getting in.

[Tman122]

Whatever quantity brings your level up to 3 PPM

[chem geek]

As was noted, you want to use whatever amount of chlorine is needed so that you still measure a residual the next time you dose/soak.

2-3 teaspoons of Dichlor will handle roughly 35-50 minutes of one person soaking or 15-25 minutes of two people soaking IF there is no ozonator.  With an ozonator, less chlorine is needed if you soak every day or two but more chlorine is needed in between soaks if you don't soak frequently (say, only on weekends).

[Bigralphy]

No ozone and the wife and I for about 45 to an hour.  I just got the tub on Monday and would love to use colorox bleach but I am unsure what other chemicals I would require.  My ta is 110 and pH 7.4.  I haven't tested for cya yet but will tomorrow. If I understand correctly I need my ta down and pH up a little before using bleach.  I am new to this and have learned a great deal on here.

Is using bleach easy for a new owner?

[chem geek]

Hot hot is your spa water?  I suspect it may not be at 104ºF if you are soaking up to an hour.  Also, I'd be surprised if two people soaking that long would have the chlorine level not get close to 0 within 24 hours.  If you are still measuring FC, then OK, but with your bather load it would normally take more chlorine.  Are you using the spa every day?

You shouldn't need to test for CYA.  Just keep track of how much chlorine you are adding.  For every 10 ppm FC added by Dichlor, it will increase CYA by 6 ppm.  How large is your spa in gallons?


You should probably get a handle on using Dichlor before you switch over to using bleach.  Before you use bleach you need to get your TA much lower (closer to 50 ppm) and add 50 ppm borates (most easily done using boric acid).  Since this is a new spa for you then you might just use the Dichlor-only method that is simpler, though you'll need to change the water sooner compared to the Dichlor-then-bleach method.  With a new spa the water won't last as long the first time anyway especially if you didn't purge it first (using Ahh-Some).

[Bigralphy]

Spa is 100f and is 350 gallons.  I just did the first shock yesterday and tested again today.  Ta was 90 and fc was 5 ppm. I have been experimenting with amounts after soaking but have been adding a tablespoon of dichlor. I am of the paranoid nature and I am always concerned about damaging the cover after adding chemical.

Thanks for your help chem geek. It's appreciated

[chem geek]

If you keep the cover off right after you add chemicals after a soak, then it will last longer.  Most of the volatile chemicals oxidizing bather waste occur during the first hour after you dose.  Even keeping the cover off for 15-30 minutes will help.

Also, if you open the cover 10 or so minutes before you enter the spa, that will also help air out any volatiles that may have built up.