After finding this site I drained my hot tub and started over yesterday. Had a few questions that I think I know the answer to, but wanted to run it by everyone here.
Hot tub specs: 515 gallon volume ozonator. Ozone runs only when main filter pump is running (minimum of 4 hours a day, plus any time it’s heating). I’m following the dichlor/bleach method recommended on this site.
After filling I did a water test with my K2006C:
FC 1.6 (tap water has a small amount, plus leftover from less than full draining)
CC 0
PH 7.5
TA 30
CH 20
CYA 0 (assuming it’s zero, I can see the dot with the test tube full, so it’s certainly less than 30).
I dosed with 1oz of dichlor to bring the FC to 10, and 3.6oz of baking soda to bring the TA to 60, then closed it up for the night to heat up to 100F.
About 12 hours later the FC dropped to 8, and another 10 hours later it was 6.5. My wife and I soaked for about 45 mins and it had dropped to 4.5. I dosed with 0.5 oz of dichlor to raise the FC to 8. CYA is probably 10-15, but too low to measure accurately. Everything else stayed about the same, TA dropped by 10, but I’m assuming that’s within the margin for the tests so leaving that for now. I have some CH increaser on order to balance the water so don’t want to raise TA too much yet. Also have some GentleSpa coming that I’ve seen recommended.
My questions:
1) Does the drop in FC over those timeframes make sense with my setup? I’ve seen estimates of 25/50% loss a day for hot tubs without/with ozone, so going from 10 to 6.5 seems to make sense.
2) When testing for CC, the sample turned the faintest shade of pink after putting in the DPD reagent. A single drop of the titrating agent cleared it up immediately. Does this count as .5 CC? Should I retest at the .2ppm sensitivity?
3) When getting in tonight at 6.5 FC, the water had a bit of chlorine smell. Is this due to the low CYA for 6.5 FC? It wasn’t bad enough to need to get out, just enough that it was noticeable.
4) Is it a problem to dose FC over the recommended FC for my CYA each night, knowing that it will drop by the next use due to ozone and off gassing? Other than the extra cost, which I don’t mind.
5) Is it safe to soak with the FC at SLAM level for my CYA? If it smells a bit I can deal with that.
6) What should I do if I’ll be away for enough days that the FC may drop below 1? Before finding this site I would have thrown a floater in there but know now that will result in too much CYA. Should I dose FC to the SLAM level (or more) and turn the temperature down? Turning off the ozone isn’t practical since it’s tied to the main filter pump.
Thanks!
Hot tub specs: 515 gallon volume ozonator. Ozone runs only when main filter pump is running (minimum of 4 hours a day, plus any time it’s heating). I’m following the dichlor/bleach method recommended on this site.
After filling I did a water test with my K2006C:
FC 1.6 (tap water has a small amount, plus leftover from less than full draining)
CC 0
PH 7.5
TA 30
CH 20
CYA 0 (assuming it’s zero, I can see the dot with the test tube full, so it’s certainly less than 30).
I dosed with 1oz of dichlor to bring the FC to 10, and 3.6oz of baking soda to bring the TA to 60, then closed it up for the night to heat up to 100F.
About 12 hours later the FC dropped to 8, and another 10 hours later it was 6.5. My wife and I soaked for about 45 mins and it had dropped to 4.5. I dosed with 0.5 oz of dichlor to raise the FC to 8. CYA is probably 10-15, but too low to measure accurately. Everything else stayed about the same, TA dropped by 10, but I’m assuming that’s within the margin for the tests so leaving that for now. I have some CH increaser on order to balance the water so don’t want to raise TA too much yet. Also have some GentleSpa coming that I’ve seen recommended.
My questions:
1) Does the drop in FC over those timeframes make sense with my setup? I’ve seen estimates of 25/50% loss a day for hot tubs without/with ozone, so going from 10 to 6.5 seems to make sense.
2) When testing for CC, the sample turned the faintest shade of pink after putting in the DPD reagent. A single drop of the titrating agent cleared it up immediately. Does this count as .5 CC? Should I retest at the .2ppm sensitivity?
3) When getting in tonight at 6.5 FC, the water had a bit of chlorine smell. Is this due to the low CYA for 6.5 FC? It wasn’t bad enough to need to get out, just enough that it was noticeable.
4) Is it a problem to dose FC over the recommended FC for my CYA each night, knowing that it will drop by the next use due to ozone and off gassing? Other than the extra cost, which I don’t mind.
5) Is it safe to soak with the FC at SLAM level for my CYA? If it smells a bit I can deal with that.
6) What should I do if I’ll be away for enough days that the FC may drop below 1? Before finding this site I would have thrown a floater in there but know now that will result in too much CYA. Should I dose FC to the SLAM level (or more) and turn the temperature down? Turning off the ozone isn’t practical since it’s tied to the main filter pump.
Thanks!