Low free chlorine, but high total chlorine

As noted, the Cl/Br test ("OTO") is the same as the powder/drop test ("FAS/DPD"). BUT the second can read to much higher levels, and is much more accurate. The first is a quick and dirty "do I have Chlorine", the second is "How much, really?". Most of us never (or hardly ever ) do the first test.

Your CYA is high, but not out of bounds. The PoolMath app will follow the chart below. Just keep your FC number in the 6-12 range. Favoring higher than lower. CYA will decrease very slowly over a longish time (months). Highish levels only a concern to those that have to add liquid Cl. With a SWCG, you just dial it up a little higher than you might with a lower CYA level.

Let your FC drift down below 10, and then test pH to get an accurate number. Only then add acid if needed. The CL reduction is dependent on sunlight, so this time of year may take a couple of days longer than it would in summer to go down.

If using PoolMath, you should turn on "CSI" tracking to keep that value in range for your pool (those of us with vinyl don't usually have to care about corrosivity of the water). Note that it is a complex relationship between all your levels and the water temp. You are in a good spot for that right now. While CH has a stronger effect on that score, since you are good, no need to add any more CH. Areas with hard water from the tap can see their CH go up as they have to add water (CH is another chem that never leaves) so it is good to know what your fill water may be doing over time. Keeping all your numbers in the recommended ranges will tend to keep the CSI reading good, also. But it can be kind of fun to play "what if" games to see what changing one level does to the overall score.

CYA Chart 2.jpg
 
Looks good...

pH test is invalid when FC > 10. Don't do anything with pH until you can test it when FC < 10.

Let your FC come down to 9 with the cell off. When you get to about 9, turn the cell on and keep your FC around 8-9 (for CYA of 60).

When FC < 10 and you can get a good pH test, lower your pH to 7.6 using muriatic acid. This will lower your TA and pH. pH will rise naturally, without raising TA. When pH gets to 8 again, repeat. When TA gets to 60-80, pH should be fairly stable around 7,8-8.0...which is just fine...stop reducing to 7.6 when your TA gets to 7.8 to 8.0.
 
I was working out of town a few days and just got to check my numbers:

FC = 3 I turned the chlorine generator back on at 50%
CC = 0.5
CYA = 60
TA = 100
Cl = 3
Br = 6
pH = 8.2
CH = 250
SWG = 3,000

I feel like I should add a gallon of muriatic acid.

Thanks for all the help.
 
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Don’t worry about the Cl and Br from the OTO side of the pH comparator. pH comparators all come double sided, your comparator is a Cl/Br OTO and pH combo. OTO can be used for both chlorine (Cl) and Bromine (Br) but any pool or spa will only be one or the other, never both. There is no bromine in your salt pool. Your OTO test result is just telling you that your total chlorine is 5ppm or higher which is no surprise since your FAS/DPD free chlorine (FC), pink to clear, test gives you a result of 23ppm.
+1 on this. Just take a peek at my avatar. I love me a good shade of "off-the-charts orange", and start to get nervous if my chlorine shows up as yellow.
 
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Double check your CH. You’ve gone from 250ppm to 145ppm? The resolution is either 10 or 25ppm so the 145 result looks dodgy.

Cl being off scale high is good for that test. That test is really only useful between fas/dpd tests to confirm that you have enough FC.

Add enough acid to bring your pH down to 7.6, no need to go any lower. ~10oz should do it. As the water cools down going into winter the CSI becomes more negative. I generally let my pH ride a little high to off set that.

Time to put your numbers into pool math or the app and track your CSI.

IMG_7841.jpeg
 
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