DownEastSpa

Huge thanks to @waterbear for the advice above. We were gone on vacation for last week, and before we left I bumped fc up with bleach to 5ppm, and I left Freshwater System on 5/10 while we were gone after making sure ph/ta etc were all in line. This morning upon returning fc was at 6, and Cc was .5 at most (barest hint of pink on cc test and instantly gone with 1 drop on 2006 kit). So, waterbear was dead on with his advice of bumping the fc for a week or so to bust the cc down from 1 to .5 Also, ph and ta never moved during the week we were gone. Ph 7.6 and ta of 60. Seems like I'm dialed in and merely need to boost salt system or add additional bleach based on bather load.

Thanks for all of the info, and you're right - I was having a brain cramp on the 10xcc formula with no cya.

Sorry should have clarified when I said boosting, I meant turning on the Boost Function on my Freshwater Salt system, which basically turns it automatically to 10 out of 10 for chlorine output for 24hrs. I physically did not add anything to tub. I'm a bit confused how the 10x CC shock level works if it's to only be used when CYA is zero?? 10x zero is still zero, right? How long uncovered (ballpark) will it take for a shocked spa to come down under 10fc from shocked level of 15-20fc? Weather is a bit cold for me to leave tub uncovered for a day, or overnight, or several hours. Does aeration help the shock-level FC come down quicker, or should that be avoided due to pH rise (I know ph will be a bit up anyways from bleach shocking)?

Thanks again @waterbearfor the info. While I'm picking your talented brain, a couple more quick questions. My CC has bounced between .6 and .8 my last few water checks in the past week or so. Other numbers - PH -7.6, TA - 60, FC- 4.6, CC - .6 or .8 CYA - 60 CH - 50 water is 3 months old, using Freshwater Salt system (salt at rec. levels) My concern is should I do a shock to try and knock the CC down/out? No major smells to the water and crystal clear looking. Obviously a bit of a clean chlorine smell when the cover is first opened. My wife and I took a 1-hour soak the other night and I thought perhaps the water and our bodies had a bit more of a chlorine smell after the soak than in the past. I realize this is normal for a long soak, and I probably should have hit the tub with a bit of bleach after the soak, but was a bit wine-fuddled. Morning after FC was 1.6 and by boosting the salt to 10 was back to 4.6 that afternoon. I normally boost system to 10 an hour or 2 ahead of time when I know more than 1 person is going in, but forgot on this one. We leave for vacation saturday for a week away, so I'm really hesitant to shock this now and then try and catch the FC and PH, etc all within a day before vacation. The hot tub can go for a week without opening the cover and the salt sytem maintains 3-5ppm FC (thanks Covid for allowing me to unwillingly test that last month!), so I'm thinking this should be fine to be dealt with when we return? Also, I see recommendations of 10x CC level for a shock to break down the CC? In other words up to 8ppm? Or do I need to go higher because of my CYA of 60? Again, CYA will be fixed with a drain in a few weeks when weather warms up (-2F this morning!) If I do a shock to break this CC down, do I shut off the Salt system completely, and then turn back on when FC levels fall back to 3-5? thanks again!

Thanks so much for the answers and reassuring info. As for the suspected scum line, my plan is to continue wiping as needed, and provided it does not get worse, simply use an ahhsome or some such spa cleaner when the weather warms up enough for a drain/fill in a couple of months. I assume that makes sense? I'm not really stressed about the hot tub and chemistry per se; I just am the type to try and read up as much as I can on an item or subject, so I can understand why things are happening, and cause/effect. The Freshwater system says target of 7.4 on PH (with range of 7.2-7.8). Is there a reason/benefit to aiming for 7.6 instead? They also recommend FC of 3, with range of 1-5. I know I've read in the past @waterbearthat you and others recommend a slightly higher FC? Would running a higher FC be detrimental to the salt system, other than a higher demand and shorter life of the cartridge?

@waterbear thanks so much for the help and the answers. As for the salt, the Taylor 1766 said 2000ppm, the Aquachek said 1700ppm, and the digital salt meter (temp correcting and calibrated to 3000ppm) read 2200ppm. I dumped and fresh-water replaced ~60 gallons (350 gallon spa) to get that in line and also to help a bit on the CYA until weather warms up. Last question - I'm getting a light white hazy line forming for 1-2" above my water line on the acrylic shell of the hot tub. Comes off every 2 weeks or so with a rag wet with hot tub water and a light scrubbing. I do not have a picture now, but from what I'm reading online this is most likely calcium scale? current PH is 7.8, TH 60 and CH is 50. Could this still be causing that slight white line? Should I get the TA down in the 50 range and try and keep my ph down closer to 7.4-7.6? I don't really care about having to wipe the white line every week or two; my larger concern is internal scaling on heater, pump etc. When I replaced my last salt cartridge there did NOT seem to be any scaling on it. Thanks again for the previous answers and the help!

Hello all! Long time reader first time poster, as they say. I've read the many great sticky threads on Ta, dichlor/bleach, etc etc over the past several weeks on here trying to educate myself. I still have a few questions. I have a new in November 2021 350 gallon spa, with the Freshwater Salt system. No major issues, but I want to stay ahead of anything that could damage tub, and be knowledgeable enough to correct issues as they pop up. First question - how does TA affect foaming? I know low pH can create foaming, but does a lower TA do the same? I have a bit of foam, but nothing I'm worried about; trying to learn, that's all. Second question - do I need to bump my FC to 5ppm once a month or so in my Freshwater Salt system? So far no issues maintaining 3ppm FC per the Freshwater manual. I bumped new fill water to 5ppm to sanitize initial fill per instruction manual on Freshwater system. The printed manual that came with the Freshwater system says yes do it as part of monthly maintenance (bump FC to 5ppm, clean filters). However the newest Freshwater PDF manual online does not say anything about a monthly bump to 5ppm FC, and my dealer said as long as system is maintaining 3ppm recommended FC you do not need to do that. Third question - I have a Taylor 2006 and have been geeking out with it for the past week or so that I've had it. I used the forums' sticky'd acid/aerate method over the past few days to get my TA down and PH to where it needs to be. I've used the recommendations I've seen on here from @waterbearand @chem geek for a low TA and pH around 7.6-7.8, and I've used the Freshwater Salt System instructions for CH and FC. question below under water info My current water info - Filled through well-water softener, and Watkins Clean Screen hose-end filter. Water is 3 months old, from brand new fill/brand new hot tub in early Nov 2021 Taylor 2006 tested water temp - 100F FC - 3.8 Salt - 1700ppm (measured with Aquachek strips. I have a Taylor 1766 kit coming Monday as well as a digital salinity tester to verify. However the gauge on my salt system on hot tub is right in the middle of the green) CH-50 TA-60 CYA -60 (high I know, but I'm in Maine so I can't do a half-drain and fill until it's not -10F every dang night. I did use Dichlor only for the initial FC bumps and to get it up and running until Freshwater system could maintain 3ppm on its own) pH - 7.6 (note this was 7.8 yesterday, but my TA was at 75-80 so I did my last 1/2 step in getting the TA down to 60, which brought my pH down to 7.6 24 hours later. I bumped up the aerators on my jets a touch so that the auto clean (turned on) will hopefully bump pH back to 7.8 My question - the Calculator Wheel that came with my Taylor 2006 kit shows my saturation index at somewhere between -.6 and -.7 which it says will be corrosive. Is this an issue? I'm well within the Freshwater Salt system limits (only big difference is they recommend TA-80 and pH 7.4). Last question - When I read the pH on the Taylor 2006 kit, I know I should do it in natural light and not in direct sun. However, should I do it with a white background? That seems to give me the easiest way to match the colors (holding sample at arms length against white corner trim of house, or with the yard-full of snow I currently have. Is that the right way to do it? Thanks so much in advance!