1 month in to TFP protocol - how do I keep chlorine more stable?

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SpaWife

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Nov 9, 2022
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1 month ago I did a purge, drain, & refill and started with the TFP protocol. So far so good!

My previous online research (& spa store advice) had advised me to keep TA btwn 80-120. So since switching to the TFP protocol, the biggest change (besides testing CYA and then switching from dichlor to bleach) has been allowing my TA to rest around the 60-70 that it seems absolutely content to stay at on its own (after having done the initial adjustment during start-up). I'm THRILLED the TA is staying steady - wow! AND with that, the pH has stayed pretty steady (7.6-8.0) without even trying. INCREDIBLE!!!! THIS in itself was worth the switch to TFP protocol!!!

I'm babysitting the chlorine the best that I can (at least every other day, but striving for every day), but it keeps going down to 0. So what is the technique for keeping it at the desired range 3-6, without it constantly bottoming out at 0? Last night it tested at 0 FC & 1 CC, so I added 1/2 cup bleach (10%) and got it up to 10.5 FC & 1 CC. This morning I retested (14 hours later) and it had fallen to 3.5 FC & 1 CC. So yay, it was within the "desired" range this morning, but I know it's just continuing to nose-dive. So this morning I added 1/3 cup bleach to bump it up so it wouldn't hit 0. Is there a better way to do this?

Other miscellaneous chlorine questions:
When I'm adding bleach, am I aiming for a certain level of FC? Over the last month I've learned if I'm aiming to hit 3-6 FC, it's just going to start lowering immediately - so aim higher, and then it'll be in that window longer (but I still hit 0, probably because I'm not at it every single day). Do I just add 1/2 cup of bleach (bumps it up by 10.5 FC) every night before bed, so it'll be at a desireable range throughout the day? If so, what do I do when I go away for a few days - throw a few cups of bleach in there??

The TFP protocol says to shock it to 12 1x/week. Does that mean add enough chlorine that would make it be at 12 FC?

At what point is it unsafe to soak in a tub? Can we soak if it's at 10? 12?

Thanks for your help!

P.S. Last night's test results:
7.6 pH
70 TA
0 FC & 1 CC
160 hardness
40 CYA
 
SpaWife said:
So what is the technique for keeping it at the desired range 3-6,
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Use it less. You aren't 'enjoying a relaxing soak'. You're making people soup. Exfoliated skin, sweat, residual soap shampoo, conditioner, fabric softener,
laundry detergent, even grosser things I won't mention, half a margatia and some hot wing sauce.

Yeah. The residuals after a soak will take some time (and some FC) to sanitize. Make sure you give it whatever it asks for.
SpaWife said:
At what point is it unsafe to soak in a tub? Can we soak if it's at 10? 12?
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Bathing/swimming is safe between min and slam for your CYA.

lc_chart.jpg

Notice the leeway between target and slam, and notice the much less leeway between target and min ? Always use that leeway above and do your best to never use the below part. :)
 
Do you bump up the FC after getting out? you have to account for the bather load that just got out. I always add some before and after. Testing will tell you what the tub needs.
 
Do you have ozone or UV? Both can deplete fc overnight. They should also eliminate cc, which leads to my next question.

SpaWife said:
Last night it tested at 0 FC & 1 CC, so I added 1/2 cup bleach (10%) and got it up to 10.5 FC & 1 CC. This morning I retested (14 hours later) and it had fallen to 3.5 FC & 1 CC.
Click to expand...
Why is your cc always 1? It shouldn't be, ozone/uv or not, so how sure are you of these results?

SpaWife said:
I did a purge
Click to expand...
With what?
 
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RDspaguy said:
Do you have ozone or UV? Both can deplete fc overnight. They should also eliminate cc, which leads to my next question.


Why is your cc always 1? It shouldn't be, ozone/uv or not, so how sure are you of these results?


With what?
Click to expand...
My CalSpa supposedly has ozone.

I have no idea why my CC is sitting at 1. I thought adding chlorine would eat up the CC and convert it back to FC, so I'm perplexed. I am very sure of these results. I'm using the Taylor test for chlorine, and it is consistently 1 CC (1 drop of the regeant turns it almost clear, and the 2nd drop makes it 100% clear). I've not experienced this before. In the past I've dabbled with the Frog (leaving the bottom half in there when I'm out of town to keep the chlorine levels up) which has caused excessive CC.; so I've just been content that since [purging, draining, refilling, &] switching to TFP protocol I'm no longer having sky high CC.

I use Aah-some for purging.

I was away for several days, and came home to a bubbly mint-smelling tub. I put a cup of bleach (10%) in, let the jets run for 20 minutes, scooped out bubbles, and went to bed. Then today I tested it and it's .5 FC and 1 CC. (8.0 pH, 90 TA) I put in oxi shock (MPS) to see if that would help - got decent bubbles (I scooped out as much as I could), with some brown gunk on the edges of the tub. Then I tested CYA, and the dot is still visible at 30 in certain lighting; so I'm going to switch back to dichlor for a bit.

Feedback is much appreciated.
 
1) A ozone system will "eat up" FC. How much it eats depends on how often it runs. Do you have a circulation pump that runs 24/7 and ozone? If so, that could very well be why you are loosing FC so quickly.

2) In simple terms, when you FC reacts with stuff on the water it turns in to CC. Additional FC will help to fully "burn off" those CC (not convert them back to FC - this is not bromine). The other thing that really helps is letting them off gas. If your hot tub has a consistent low CC reading, try opening the cover and running the jets for a minute or two before taking your sample for measurement.

3) You do seem to be using a lot of FC. As a comparison, my smaller tub with ozone (but not 24/7 ozone, it only runs during a filtration cycle) uses just about 2oz of bleach a day with no additional bather load. I suspect you have a 24/7 ozone system in there (either that or something is really growing somewhere)
 
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RDspaguy said:
The chlorine used in the spa frog reads as cc for some reason. Perhaps there was enough residual water after the purge to give you a false reading. Otherwise I see no reason for that.
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Interesting. Well I've chucked the Frog (and the water that went with it) since mid-July. So hopefully if it's from risidual I'll see that correct over time - especially with more purges (which I'm hoping to not do as frequently now that I've ditched the Frog!).
 
phonedave said:
1) A ozone system will "eat up" FC. How much it eats depends on how often it runs. Do you have a circulation pump that runs 24/7 and ozone? If so, that could very well be why you are loosing FC so quickly.

2) In simple terms, when you FC reacts with stuff on the water it turns in to CC. Additional FC will help to fully "burn off" those CC (not convert them back to FC - this is not bromine). The other thing that really helps is letting them off gas. If your hot tub has a consistent low CC reading, try opening the cover and running the jets for a minute or two before taking your sample for measurement.

3) You do seem to be using a lot of FC. As a comparison, my smaller tub with ozone (but not 24/7 ozone, it only runs during a filtration cycle) uses just about 2oz of bleach a day with no additional bather load. I suspect you have a 24/7 ozone system in there (either that or something is really growing somewhere)
Click to expand...
I see. According to CalSpa, the Ozone runs whenever the filter is running. I usually filter 6 hours/day. When I've been away and am fighting cloudiness, I bump it to 10 hours/day. I've been going through 1/2 cup (4 oz) of 10% bleach daily, and that's just bouncing it from 0 to 7.3 FC each day. I know that isn't proper - I'm supposed to keep it above 3... but I haven't mastered that yet.

In my measuring & notetaking I've learned that my spa consumes/loses 6 FC every 12 hours, without using it, with filter running 6 hours/day.

Thanks for the tip on CC. I hadn't caught that it "burns off" vs "converting back to FC", but it does make sense.

My current water balance is this:
85 TA
8.1 pH
180 hardness
40 CYA
11FC, 2 CC (I just added bleach)
97 degrees F
 
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I have an update of sorts, and am hoping you might understand what's going on.

I ran out of the bottle of bleach that I was using, so now I'm using the other bottle I bought... and now my chlorine is extremely stable! I'm hardly having to put any in. For example, in the last 8.5 hours the hot tub has only lost 1 FC; another time I measured, it lost 3 FC in 12 hours. With the other bottle, it was consistently losing .5 FC every hour (6 FC in 12 hours). (These were all measured over time that we weren't using it - so no bathing load was affecting these numbers.)

The first bottle of bleach I used was 10%. It's the Pool Essentials Chlorinating Liquid from Walmart.

The second bottle of bleach I've been using (since running out of the 1st bottle) is 7.5%, and is the Great Value Bleach from Walmart. My bottle is just very slightly different than what is pictured there - it has an icon saying "With Fabric Protection" and has a gold shield with red stars. I really did my best to buy bleach with nothing else in it, but I didn't catch that it said this when I picked it up (having ordered it via their app). This one lists the same ingredients as it shows in that link.

Do you have any insight on why my hot tub's chlorine level is so much more stable with this 7.5% rather than the 10% I had been using?
 
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