I recently moved to Houston, and I bought a hot tub a couple of weeks ago for these cold winters and mild summers 
Anyway, I've had two other houses with two different pools, and have used the TFP method without a hitch. So far, everything is going fine with my spa (water is clear as can be), but I've still got some questions I suppose. Here are the details.
Dr. Wellness G-14 Spa - 450 gal, 92 total jets, 3 6HP pumps, waterfall, 92"x92"x36"
Water Chemistry 1/8/17:
FC - 5.5
PH - 8 (2 drops of acid demand got me to 7.6)
TA - 60
CH - 200
CYA - 30-35
Borates - 50 (Haven't actually measured--simply added 15 oz of boric acid recently)
Temp - 85 (Knew I wouldn't be in it over the weekend so I turned it down)
Problem #1: So I've been fighting this PH getting up to 8. The way I read the chlorine spa sticky was that if you have your TA down far enough, the jets won't tend to cause the PH to drift up that quickly. Whether my TA is 50 or 60, if I get in the spa and turn the jets on for about 30 minutes, my PH will be 8. If my TA is 50 or 60, should my PH be going up after a short time with the jets on? Granted, when I get in, 2 if not 3 of the pumps are on, and I like to open the aerator valves to get a better massage. Anyway, that's problem number one--PH rising more than expected for my TA level--but maybe that's normal and the sticky is ambiguous on this point (in my opinion)?
Problem #2: My supposed volume is 450 gallons. However, if I go to the pool calculator and I want to raise my chlorine 3 ppm, it says I need 60mL of 8.25% bleach. However, if I add 60mL and re-measure an hour or so later, I get an increase of about 5 ppm. I've tried it twice just to see. So for pool calculator purposes, I've been saying I have a 400 gal hot tub, but maybe I should say it's even less? because of problem #3.
Problem #3: So, I'm now using 400 gallons as my volume. Given a TA of 60 and a borate of 50, I'm to add 39 ml of 31.45% Muriatic Acid. I bought some graduated cylinders for $5 on amazon, and I measured out 39 ml, and dumped it in. But I also see that it's going to put my TA below 50, so I add about 10g of baking soda to bring my TA to 50. I checked today, and my PH was 7.4 (lower than expected) and my TA was 50 (expected). Now, with the TA test, it could be anywhere from like 45 to 55ish, right? But the PH dropping to 7.4 again makes me think that maybe I should be using less volume for the pool calculator than what the manufacturer says? I don't have exact numbers, but I know every time I add acid, it drops farther than expected. The outside dimensions match what they say they should be, but I question the volume. Maybe I'll get a fill meter or something.
Finally, when plugging my current values into the pool calculator vs goal values, I see that my CSI with the numbers provided above is exactly 0. Which seems pretty good, but the PH is 8 which is out of range. Then I see if I lower my PH to 7.6 and TA to 50, it reduces my CSI to -.39 which is still in the ok range, but a 0 looks pretty good, right? I think the answer here is that I need to get my PH in range and not be super concerned with the CSI. It’s a fiberglass spa anyway. This was just an observation.
Thanks for reading and for any help. All comments, hints, tips, tricks, or additional questions are appreciated. And finally, Roll Tide!
PS: for some reason, it won't let me update my signature to remove the old info and update with new :S
Anyway, I've had two other houses with two different pools, and have used the TFP method without a hitch. So far, everything is going fine with my spa (water is clear as can be), but I've still got some questions I suppose. Here are the details. Dr. Wellness G-14 Spa - 450 gal, 92 total jets, 3 6HP pumps, waterfall, 92"x92"x36"
Water Chemistry 1/8/17:
FC - 5.5
PH - 8 (2 drops of acid demand got me to 7.6)
TA - 60
CH - 200
CYA - 30-35
Borates - 50 (Haven't actually measured--simply added 15 oz of boric acid recently)
Temp - 85 (Knew I wouldn't be in it over the weekend so I turned it down)
Problem #1: So I've been fighting this PH getting up to 8. The way I read the chlorine spa sticky was that if you have your TA down far enough, the jets won't tend to cause the PH to drift up that quickly. Whether my TA is 50 or 60, if I get in the spa and turn the jets on for about 30 minutes, my PH will be 8. If my TA is 50 or 60, should my PH be going up after a short time with the jets on? Granted, when I get in, 2 if not 3 of the pumps are on, and I like to open the aerator valves to get a better massage. Anyway, that's problem number one--PH rising more than expected for my TA level--but maybe that's normal and the sticky is ambiguous on this point (in my opinion)?
Problem #2: My supposed volume is 450 gallons. However, if I go to the pool calculator and I want to raise my chlorine 3 ppm, it says I need 60mL of 8.25% bleach. However, if I add 60mL and re-measure an hour or so later, I get an increase of about 5 ppm. I've tried it twice just to see. So for pool calculator purposes, I've been saying I have a 400 gal hot tub, but maybe I should say it's even less? because of problem #3.
Problem #3: So, I'm now using 400 gallons as my volume. Given a TA of 60 and a borate of 50, I'm to add 39 ml of 31.45% Muriatic Acid. I bought some graduated cylinders for $5 on amazon, and I measured out 39 ml, and dumped it in. But I also see that it's going to put my TA below 50, so I add about 10g of baking soda to bring my TA to 50. I checked today, and my PH was 7.4 (lower than expected) and my TA was 50 (expected). Now, with the TA test, it could be anywhere from like 45 to 55ish, right? But the PH dropping to 7.4 again makes me think that maybe I should be using less volume for the pool calculator than what the manufacturer says? I don't have exact numbers, but I know every time I add acid, it drops farther than expected. The outside dimensions match what they say they should be, but I question the volume. Maybe I'll get a fill meter or something.
Finally, when plugging my current values into the pool calculator vs goal values, I see that my CSI with the numbers provided above is exactly 0. Which seems pretty good, but the PH is 8 which is out of range. Then I see if I lower my PH to 7.6 and TA to 50, it reduces my CSI to -.39 which is still in the ok range, but a 0 looks pretty good, right? I think the answer here is that I need to get my PH in range and not be super concerned with the CSI. It’s a fiberglass spa anyway. This was just an observation.
Thanks for reading and for any help. All comments, hints, tips, tricks, or additional questions are appreciated. And finally, Roll Tide!
PS: for some reason, it won't let me update my signature to remove the old info and update with new :S
