Used tub, up and running, numbers check?

Oct 9, 2018
15
Kansas City MO
Alright well I got my used 230gal tub purged with ahh-some 2x over the weekend. The first round got all kinds of gunk out! The second round only had a little bit of gunk. I skimmed it off the foam, and continually cleaned the sides and water lines until it stopped producing anything at all, then the last drain over night sat. Sunday morning was a deep clean, rinse, and fill.

I then tested my new clean water before adjustments and had:

CH: 80
TA: 80
PH: 8.0+

I worked on CH first, added 5tbsp Calcium in an attempt to raise it to 150, I then added 2oz MA in an attempt to lower TA to 50. And finally added just over .5oz dichlor to try and get FC to 10. I then closed it up after an hour and let it be overnight.

This evening when I got home from work at 5:30 I ran my tests again and got:

CH: 150 (right on the mark!)
TA: 70 (not much change with 2oz, only 10ppm)
pH: 8.0 (still high)
FC: 6.6
CC: .4

So I added 2oz more of MA to tackle the TA and pH. I waited 3 hours then tested again and got:

CH: 150
TA: 50 (it worked!)
pH: 7.2 (just a tad low but I did not aerate before testing)
FC: 6.6
CC: .4

Even though the FC was a bit higher than 5ppm I went ahead and took the inaugural soak. I couldn't wait anymore, this project has been ongoing since June! The outside air temp was 40, the tub was up to 102, and it felt FANTASTIC!! I soaked for exactly 1hr by myself with swim trunks, (I don't have any means of privacy just yet, next project!) and then tested FC again to get a baseline for usage:

FC: 3.6
CC: .6 (not sure why this raised a tick, is it supposed to?)

Once I was all done, I added 3.1grams dichlor which pool calc says should raise FC by 2ppm so should have put me back to 5.6ppm.

I'm looking for opinions on everything, hopefully I did this all correctly?? Will the CC continue to rise? To be honest I don't really understand the combined chlorine just yet. Does 3ppm FC consumption per bather hour sound correct for a small tub like this? Will I have to go up past the 5ppm FC if my wife is to join me and make it 2 bather hours in one setting? That would mean a consumption of 6ppm leaving the FC to hit 0 before were done if we stay in for one hour. If thats the case do I bump the dose up prior to compensate? Is that safe?

Do I need to continue testing the CH & TA each time, or can I move that to the 1x per week testing and just daily test FC & pH?

And finally what do I do now to just maintain? Obviously I add dichlor each day to keep the FC up so it's ready to use, and when done soaking replace what has been used, but then what??

Thanks for the help!
 
Fc demand after using Ahh some will be greater for a few days.

FC 10 and under is safe to soak

After me and my wife soak for an hour I'll dose it worry 2-3 oz of shock. Then I test the next day. My spa is Bromine, a little different, but same concept
 
If you used the tub FC will continue to drop for a while after getting out of the tub as the waste isn't dealt with immediately and will place a load on the your FC for a little while (at least that is what i have witnessed). I just played around with it for a week or two to figure out approximately how much bleach to add after my wife and I are in it for an hour.

My guess on the CC is that was waste that was being dealt with. I have noticed that my CC will fluctuate from 0 to 1.5 depending on usage and amount of time the tub is open.

Again someone with better answers will probably be along this is just what I have noticed over the past 4 weeks of using the TFP method on my Hot Tub.
 
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