Hello all,
We bought a house with a 1-year-old 460 gal Clearwater Spas hot tub last year. The tub has a factory-installed ozonator. At first we were following the home sellers' recommendations of shocking with dichlor/trichlor once a week, and keeping the water in the industry recommended ranges (eg TA around 80, CH around 200, FC around 3-5ppm, pH around 7.6) and using dichlor tablets in a floater throughout the week to maintain FC levels. Over time, of course, we noticed more and more problems keeping the tub clean, especially when we had to leave town for a week and came back to discover a green cloudy tinge in the water which I'm assuming was algae (though we all know what happens when we assume!) with FC being almost zero and high CC despite continually using the floater/dichlor tabs. That's what got me looking into hot tub chemistry to begin with, and before I found this forum and the Pool Math app I had already run across chem geek at another site, and used his explanations to write my own spreadsheet which wound up matching Pool Math pretty closely. I bought the Taylor kit that measures FC, pH, TA, CH, and CYA.
So the last time I drained/seaklear'ed/washed/filled the tub (Nov 30 2021), I switched to the method of using dichlor at first to get CYA up--I was shooting for 30 but overshot a bit, it's around 45 now--and added borates to around 50 ppm as a buffer. I then used liquid bleach daily to keep FC between 4-8 ppm, which requires adding 2-3oz of 12.5% liquid bleach daily. We had to leave town last week for a family emergency, so the afternoon we left I did a SLAM to get the FC to 18-20 ppm per Pool Math's recommendation, and left town Wednesday afternoon. We got back on Sunday evening and by the time we got home, FC was zero and the water was green and cloudy again. I did another SLAM to 18 ppm on Sunday evening, and by yesterday morning the FC was down to 3ppm. The water was definitely less green and more clear but still present, so I SLAM'd again to get it up to 18 ppm. I also removed and washed the filters yesterday afternoon.
This morning, the test results earlier this morning were:
FC: around 6ppm (darker than 5, lighter than 7.5, so guessing here but close)
CC: 0
pH: 8
TA: 60
CH: 260 (need to add some water due to dehydration, this always brings it back to 250)
CYA: around 45
Borates: around 50, test strips aren't the easiest to color match
The greenish tinge appears gone, though the water does still appear slightly cloudy. I added muriatic acid and readings currently are:
FC: 5 ppm
CC: 0
pH: 7.6
TA: 40
CH: 260
CYA: ~45
Bortates: ~50
I think I have the problem solved now and will continue to monitor and add bleach again as before. But I now have a couple of questions I'm hoping those with more experience can weigh in on:
1) How do you keep your pool clean when you travel?? I think SLAM'ing on a Friday afternoon before we leave town for a weekend will work just fine, but in tests I've done before it appears that SLAMing to a FC level of 18 ppm (when starting with clear water) results in a FC level of around 10 ppm the next day, and around 3 ppm by the second day. That works for a weekend as I can SLAM Friday afternoons when we're off doing outdoor activities, but leaving it unattended for even 4 days results in cloudy, green water again. What do people recommend to prevent this problem?
2) I did add a little more bleach when we left town Wednesday afternoon than the recommended amount for an 18 ppm SLAM, as I was trying to extend the time before the FC was all broken down. When I washed the filters yesterday, there were a fair number of small black specks on the filter, I picked off a larger one and rolled it around between my fingers and it looks and feels like little rubber bits. Did I damage the seals by using liquid bleach to get the FC level that high? I know many here advocate the liquid bleach method, though hot tub dealers all say avoid liquid bleach, claiming it will in fact damage seals and o-rings. Is that true, or marketing hype to sell higher-cost pool and spa chemicals?
At this point I'm considering going with some kind of mineral method eg Frog @ease, Nature2 or some such, because we do leave town in the summers for extended periods up to a couple of weeks and I can't have the spa growing algae and requiring a drain and refill every time we do.
Thanks for any help or advice you can give!
We bought a house with a 1-year-old 460 gal Clearwater Spas hot tub last year. The tub has a factory-installed ozonator. At first we were following the home sellers' recommendations of shocking with dichlor/trichlor once a week, and keeping the water in the industry recommended ranges (eg TA around 80, CH around 200, FC around 3-5ppm, pH around 7.6) and using dichlor tablets in a floater throughout the week to maintain FC levels. Over time, of course, we noticed more and more problems keeping the tub clean, especially when we had to leave town for a week and came back to discover a green cloudy tinge in the water which I'm assuming was algae (though we all know what happens when we assume!) with FC being almost zero and high CC despite continually using the floater/dichlor tabs. That's what got me looking into hot tub chemistry to begin with, and before I found this forum and the Pool Math app I had already run across chem geek at another site, and used his explanations to write my own spreadsheet which wound up matching Pool Math pretty closely. I bought the Taylor kit that measures FC, pH, TA, CH, and CYA.
So the last time I drained/seaklear'ed/washed/filled the tub (Nov 30 2021), I switched to the method of using dichlor at first to get CYA up--I was shooting for 30 but overshot a bit, it's around 45 now--and added borates to around 50 ppm as a buffer. I then used liquid bleach daily to keep FC between 4-8 ppm, which requires adding 2-3oz of 12.5% liquid bleach daily. We had to leave town last week for a family emergency, so the afternoon we left I did a SLAM to get the FC to 18-20 ppm per Pool Math's recommendation, and left town Wednesday afternoon. We got back on Sunday evening and by the time we got home, FC was zero and the water was green and cloudy again. I did another SLAM to 18 ppm on Sunday evening, and by yesterday morning the FC was down to 3ppm. The water was definitely less green and more clear but still present, so I SLAM'd again to get it up to 18 ppm. I also removed and washed the filters yesterday afternoon.
This morning, the test results earlier this morning were:
FC: around 6ppm (darker than 5, lighter than 7.5, so guessing here but close)
CC: 0
pH: 8
TA: 60
CH: 260 (need to add some water due to dehydration, this always brings it back to 250)
CYA: around 45
Borates: around 50, test strips aren't the easiest to color match
The greenish tinge appears gone, though the water does still appear slightly cloudy. I added muriatic acid and readings currently are:
FC: 5 ppm
CC: 0
pH: 7.6
TA: 40
CH: 260
CYA: ~45
Bortates: ~50
I think I have the problem solved now and will continue to monitor and add bleach again as before. But I now have a couple of questions I'm hoping those with more experience can weigh in on:
1) How do you keep your pool clean when you travel?? I think SLAM'ing on a Friday afternoon before we leave town for a weekend will work just fine, but in tests I've done before it appears that SLAMing to a FC level of 18 ppm (when starting with clear water) results in a FC level of around 10 ppm the next day, and around 3 ppm by the second day. That works for a weekend as I can SLAM Friday afternoons when we're off doing outdoor activities, but leaving it unattended for even 4 days results in cloudy, green water again. What do people recommend to prevent this problem?
2) I did add a little more bleach when we left town Wednesday afternoon than the recommended amount for an 18 ppm SLAM, as I was trying to extend the time before the FC was all broken down. When I washed the filters yesterday, there were a fair number of small black specks on the filter, I picked off a larger one and rolled it around between my fingers and it looks and feels like little rubber bits. Did I damage the seals by using liquid bleach to get the FC level that high? I know many here advocate the liquid bleach method, though hot tub dealers all say avoid liquid bleach, claiming it will in fact damage seals and o-rings. Is that true, or marketing hype to sell higher-cost pool and spa chemicals?
At this point I'm considering going with some kind of mineral method eg Frog @ease, Nature2 or some such, because we do leave town in the summers for extended periods up to a couple of weeks and I can't have the spa growing algae and requiring a drain and refill every time we do.
Thanks for any help or advice you can give!
Since I used a low chlorine/ozone system for well over a decade, and recommended
& magic mineral potions 
are not the answer & cause more problems than they solve.
It. No extra stuff necessary. Improperly balanced ph carries a much higher risk of galvanic or other types of corrosion than the salt or the tiny amounts of electrolysis produced by the swg will. 