YIKES - green tub.

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Yeah, the SWG is important and quite honest its working great....
So this morning I balanced the PH and dropped temp to 100.

FC is now 4ppm - this is about 15 hours of tub time. so the SWG is definitely working well. Maybe the ozone is junk, but the SWG seems to be doing really well.
CC - 0
PH - 7.7
TA - 50
CYA 35 - dropped a touch, so I bumped it back to 50.
Calc - 100
 
Hope you don't mind me chiming in here ... just wondering why you are bothering w/CYA? As I understand it for a closed hot tub it's really not necessary because you won't be losing chlorine to a sunlight. Based on what people here have said I have not bothered to check it in my spa.
I have also been keeping my spa at 104 this past winter; not crazy about the cost but as you say, I don't necessarily know when I'll get in, and I want it to be ready to go when I feel like using it. I use it pretty much every day anyway so not sure there would be much benefit to turning it down between uses. Is it really bad to keep it so high? If so, what is the recommended temp to keep it at, and how long should I expect it to take to heat up from that to 104, so I can try to increase it before I want to get in?
 
No, i dont mind at all... All I know is that if my CYA drops to zero my FC goes with it. Whether thats strange or not...
My SWG is working just fine and has had zero problem keeping up but it seems I need CYA in the tub.
 
Hot tubs still need cyanuric acid stabilizer if chlorine is used. CYA in chlorinated water serves 2 purposes - first, it reduces the loss of chlorine to UV photolysis, and second, CYA acts as a chlorine buffer holding most (~95%) of the chlorine in reserve so that the active chlorine (hypochlorous acid/hypochlorite) is reduced to minimal levels. Without CYA in the water, the chlorine added would all be active chlorine and the water would be very irritating and harsh to bath in.
 
So I think you've seen from my other posts, I switched to an SWG a week ago, and so far I haven't added any chlorine - just the salt to get the SWG going. I'm using it daily and have had two people in it three times now, and the water feels great and looks amazing. I have been checking the FC and CC levels and it all seems good - FC has been in the 3-4 range the SWG finishes a cycle, and CC has been 0-0.5. Do I really care about CYA at this point?
 
joecooler said:
So I think you've seen from my other posts, I switched to an SWG a week ago, and so far I haven't added any chlorine - just the salt to get the SWG going. I'm using it daily and have had two people in it three times now, and the water feels great and looks amazing. I have been checking the FC and CC levels and it all seems good - FC has been in the 3-4 range the SWG finishes a cycle, and CC has been 0-0.5. Do I really care about CYA at this point?
Click to expand...

I would not bathe in a tub with that much unstabilized chlorine in it. At 3ppm and zero CYA you would have 1.5ppm hypochlorous acid (HOCl) at a pH if 7.5 which is 30 times the amount necessary for disinfection (50ppb or 0.05ppm HOCl is enough to kill bacteria). The water will be very harsh on clothing, skin, hair and eyes. Without the CYA to moderate the reaction rates, the chemistry favors the reactions that form the harshest CC, nitrogen trichloride, which will offgas with aeration but give the tub that commercial pool smell. You are also forming organic CCs which you can’t measure like chloroform and chlorourea, trihalomethanes like haloacetic acid and other disinfection byproducts (DBPs). These are all chemicals that can not be measured with a standard test kit but can cause people to feel ill.

TFP recommends always having a minimum CYA concentration of 30ppm in a chlorinated hot tub as it is the safest way to use chlorine. Algae is almost never an issue in hot tubs so there’s no reason to fear having high CYA levels. Bacteria and pathogens are easily neutralized with an FC between 2-3ppm and a CYA of 30ppm. This is all based on the science of chlorinated pool and spa water and the thousands of hot tub owners that regularly use the dichlor/bleach method of hot tub startup. If you wish to use dichlor to start with and then add salt and let the SWG do the chlorine maintenance, that’s totally fine too but you should always have CYA in the water for bather comfort and safety.
 
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Interesting. I will check my CYA tonight - haven't done that yet. I wonder if it is actually above 0, given that no one who has been in it has experienced the discomfort you are talking about.

I've been wanting to avoid adding dichlor because my experience w/my first tub full of water was not great ... over time the CYA levels went through the roof and the chlorine wasn't able to do it's job. The water also felt increasingly "chemically" to use the technical term. :D Of course I wasn't following the TFP system (was using dichlor instead of bleach) so that was part of the problem. Anyway if my CYA is low I will follow the TFP method and add some dichlor to bring it up. You guys haven't steered me wrong yet!
 
have you read the chlorine guide (sticky in this forum) for how to use dichlor? Basically I stopped worrying about dichlor actually... I just use my SWG and bleach. Easier than worrying about when to use dichlor and when to back off and use bleach.
 
Dichlor is simply one way to add both chlorine and CYA. If you prefer to add the CYA as a separate addition and get all 30ppm at once, then there are liquid forms of CYA available to do that quickly. But, no matter the method of addition, CYA is just as necessary in a hot tub as it is in a swimming pool.
 
I have read the sticky, many times! :D I had been thinking I would punt on dichlor and let the SWG take care of chlorine, and shock it after heavy use (ie, more than a couple of people in it at a time). However, from what Matt is saying, it sounds like we do need to be sure we have some CYA in there, which the SWG and bleach won't accomplish. So depending on what I read my CYA at I may turn off the SWG for a couple of days and dose it w/dichlor to get the CYA level to 30. Then it sounds like I can go back to relying on the SWG, and testing CYA periodically to verify it's at 30 (and adding more dichlor when/if it drops).
 

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Joecooler . You already have chlorine in the tub. I would just buy liquid CYA or Granular CYA and add what pool math says. Your chlorine is stable and good so all you need is the CYA. For every 10ppm of FC dichlor adds, it adds 9ppm of CYA... So it would take about 33+ FC just to get your CYA up to level (30). So I wouldnt recommend that as your option.
Just get some CYA and get it to 30.
a 450gal tub from 0-30 is 1.6oz of granular CYA FYI
 
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I tested my CYA this morning and it is definitely low .... filled the testkit cylinder to the top and water was just getting a little bit cloudy. Thanks for the advice, I was thinking I'd just shut off the SWG for a bit and add dichlor until the CYA hit 30, but maybe it's easier to just add CYA straight up.
 
Yeah If you shut off your SWG it would take you weeks to slowly add enough dichlor to get your CYA up to 30. You would be adding like 3-4ppm per dose to maintain proper FC levels without going crazy, and it would take approx 10 doses to get your CYA up to 30. Id just do the CYA route on its own :)
 
I am using the tub daily, and my SWG is running at least 1 cycle/day and it generates around that much - 3-4ppm - per cycle, so in theory I could probably get it up in 10 days right? Or maybe faster? It seems like I see folks talking about hitting their tub w/10-12ppm sometimes, and just leave to cover off to burn the FC off faster. Am I missing something here? I have a bottle of dichlor granules I bought a week before I realized I had to purge, so I've got dichlor to burn!
 
yep that is it... or you can get liquid. With granular CYA its recommended to put it in a sock and hang the sock over your filter basket and let it slowly dissolve that way. at least thats what ive done based on some other recomendations
 

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