Keep adding more dichlor till the FC holds? I've been testing the CYA and it comes to about 33, but maybe that's not enough to hold it good?
Itchy rash. What to do with hot tub water?
- Thread starter davesurfer
- Start date
No, keep adding more bleach until the FC level holds between 3 and 5ppm. CYA at 25-35 is fine, leave it there. It is important not to let FC drop to 0 before you add more bleach. So, either add enough so that it will be 3-5 the next time you get in and/or test or test and add a smaller amount a few times. I wasn't adding enough bleach to kill everything and retain a residual FC level the next time I got in the tub or tested and added more. Test about 15 minutes after you add bleach and see where it is. Mine would drop quickly at first. If it stays around 5 then test again in an hour to see if it is still holding.
Keep some notes on how much you add and what the residual level is and you will figure out what the normal chlorine demand is.
Keep some notes on how much you add and what the residual level is and you will figure out what the normal chlorine demand is.
Ok, so far I have to add about 200 ml of bleach per day. And my tub is a Sundance Calypso 6 seater, I think it's 1500 L. PoolMath tells me only to add 78ml or so but I find I have to over double that to get my goal FC
200ml of bleach is very close to our long term daily average (9 months) of bleach additions in our tub. Others suggest that this is more than what they need, but that's what we need to add in order to keep free chlorine in the tub as indicated by testing.
I've also found through testing that cya disappears at a faster rate than expected as well. Something like 4-6ppm per week.
I suggest that you go ahead and add what chlorine you need to, in order to keep your FC and CYA numbers in the appropriate range as indicated by your testing. That's what we do.
Just as an example, two nights ago we had some people over for a party, so there was 5 people in the tub for quite a few hours. Over the past 24 hours, I've added 2 cups (480ml) of bleach (8.25), plus a tablespoon of the granulated stabilized chlorine powder (another 12ppm fc/11ppm cya) to keep up with the additional chlorine demand, and to replace cya from all the splash out. I'll still need to test tomorrow to see if FC is holding like normal.
The tub makers and retailers set us up for failure in my opinion by telling us to not use liquid chlorine for sanitation. At the rate of chlorine addition that we do, cya would build something like 100ppm per week. That is not sustainable without problems with bacteria growth coming up in short order. They essentially put their profit motivations to sell chlorine powder ahead of their customers health. Hot tub rash is no fun, and Legionnaire’s disease isn't something I care to deal with. People die from it. (google it).
I've also found through testing that cya disappears at a faster rate than expected as well. Something like 4-6ppm per week.
I suggest that you go ahead and add what chlorine you need to, in order to keep your FC and CYA numbers in the appropriate range as indicated by your testing. That's what we do.
Just as an example, two nights ago we had some people over for a party, so there was 5 people in the tub for quite a few hours. Over the past 24 hours, I've added 2 cups (480ml) of bleach (8.25), plus a tablespoon of the granulated stabilized chlorine powder (another 12ppm fc/11ppm cya) to keep up with the additional chlorine demand, and to replace cya from all the splash out. I'll still need to test tomorrow to see if FC is holding like normal.
The tub makers and retailers set us up for failure in my opinion by telling us to not use liquid chlorine for sanitation. At the rate of chlorine addition that we do, cya would build something like 100ppm per week. That is not sustainable without problems with bacteria growth coming up in short order. They essentially put their profit motivations to sell chlorine powder ahead of their customers health. Hot tub rash is no fun, and Legionnaire’s disease isn't something I care to deal with. People die from it. (google it).
Yeah I definitely think it was caused from when I was using trichlor tabs...and they dissolve so much there was insane amounts of CYA in there.
But about losing the CYA, I thought it stayed in the water until it was dumped? But I guess if you have lots of splash out and are replacing water often that would make sense.
Retailers setting up for failure is true. I've spoken to lots of salespeople who cringe and look at me funny when I was asking them about adding bleach to the hot tub...
But yeah, I think what I'm going to do anyways, is do a purge with the Ahh-some cleaner, dump the tub and re-fill, add the dichlor then start doing bleach as I'm doing now. Just to make sure the plumbing is properly cleaned out. I don't know the history of this tub and it was bought in '94 and we only had the house for a year....
- May 23, 2015
- 24,472
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
CYA is lost through splash-out (drag-out is probably a better term for hot tubs) and it does get oxidized (slowly) by chlorine. The loss of rate of CYA from chlorine oxidation in a pool is roughly 0.2ppm/day or a few ppm per month. In a hot tub, the loss rate due to chlorine oxidation is higher because the temperature is higher most of the time and the loss rate can be as high as 5ppm/month or more (it also depends on how high you let the FC get after dosing with chlorine). So it is not unusual at all to see some loss of CYA in a well used hot tub.
If your interested in the chemistry of CYA degradation, see this post - Degradation of Cyanuric Acid (CYA)
If your interested in the chemistry of CYA degradation, see this post - Degradation of Cyanuric Acid (CYA)
Wow that's 6 ppm a month. So I should really be testing CYA once a month or just the first month after and then add dichlor to top it up...once I know how much it depletes I don't have to test any more. Thanks for the info!
- May 23, 2015
- 24,472
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
It's not a bad idea to run the CYA test once per month to track you CYA loss rate. Although at 5ppm/month, you're right on the edge of what you can measure with the rest so it might be best to wait two months to see a change.
Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006
- May 22, 2013
- 2,796
- Pool Size
- 12000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
" I do have Chlorox bleach, but it's the "concentrated" kind"
Concentrated is fine. You want to stay away from scented or splashless. With the splashless stuff it's thicker and something in there reacts poorly to being in a pool or pump and will create a lot of foam.
Concentrated is fine. You want to stay away from scented or splashless. With the splashless stuff it's thicker and something in there reacts poorly to being in a pool or pump and will create a lot of foam.
I have started having the same problem with the red rash. It's mainly on my calves, back and sides of my arms. It drives me crazy!!!! I bought my hot tub in April of 2015 and kept my temp. about 94 degrees during the summer. Then winter came and i raised my temp. to about 98.That was in October. That's when i started having trouble. I use bromine in my tub because that's what the pool store set me up with. Was wondering if anyone thinks i should switch to chlorine? I am very new to this.
Thanks
Thanks
- May 23, 2015
- 24,472
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
When was the last time your water was exchanged? How have you been testing your water and what is the procedure you use for dosing bromide? Have you deep cleaned your hot tub using a biofilm remover like Ahh-some? Hot tub sanitation needs to be managed daily. If at anytime your sanitizer level dropped to 0 for any length of time, then the hot tub water will become a perfect environment for bacteria to grow in. This can lead to the formation of biofilms which are impossibly hard for sanitizers of any type to penetrate.
You condition sounds like it could be Hot Tub Rash (also known as Pseudomonas aeruginosa folliculitis) but it can also be a case of skin abrasion from sitting in front of the jets too long. People don't often consider how mechanically abrasive a jet of water can be especially when the skin is softened from soaking in water.
I changed my water in November of 2015. I use a flaoting dispencer with 1 inch bromine tablets in it. I also use bromine concentrated granular once a week as a shock. I use test strips but i now know they are not good. I have already ordered a test kit.
- May 23, 2015
- 24,472
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Good for you ordering a test kit; strips are really not accurate. I'd recommend changing water more frequently than once every 7 months if the hot tub is used very frequently (daily) and using a deep-cleaning product like Ahh-some to clean out the plumbing (even brand new hot tubs can have significant films built up on the internal plumbing). Some people find controlling the bromine levels to be difficult with a tab floater. This is why daily water testing is critical in order to know if your sanitizer level is adequate. Does the hot tub have an ozonator built into it to help oxidize the bromide back into bromine? If not, or if it's not functioning well, then you might need supplemental oxidation from chlorine to get enough of a bromine concentration.
If you want to convert the tub to chlorine, that can be done at your next water change. Many TFP hot tub owners find chlorine to be a better (and MUCH cheaper) alternative to bromine.
Thanks. Yes 7 months was to long. But we were in a very bad drought here in Texas. All is better now with our water situation so I will change more often. Thanks for a answering my question. I do think I will switch to chlorine.
- May 23, 2015
- 24,472
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
This thread has all the information you'll need for converting to chlorine - How do I use Chlorine in my Spa (or pool)?)
I recommend when you are ready to empty the hot tub that you get the Ahh-some product and deep clean the hot tub before converting. You can use the old, brominated water in the tub, flush the system with Ahh-some and then refill the hot tub with fresh water and start using chlorine. Follow all of the instructions for the Ahh-some product carefully and do not over-dose it; it is VERY powerful.
Good luck and ask questions (start a new thread though) if you need help.
My wife and I use our hot tub every night for 15-20 minutes and at times have both suffered the itchy skin, occasionally with small red bumps. I too looked long and hard for solutions, but I think in our case it is more attributable to dry skin (especially in the winter months) than it is to water chemistry. Our spa died several weeks ago, and during the time we have not had it running, I have still had some itchy patches in the same places I have gotten them when using the spa.
Interesting good to know! Yeah I wonder if it was that, I mean I would sit in the corner and have the jets blast at my back and sides for a long time every day, that might have caused the issue I'm thinking.
- - - Updated - - -
Just did the Ahh-some treatment....holy cow the foam was almost coming out of the tub! It had a bit of a yellowish tinge, which was good, so must've been some pipe crud and stuff. I sprayed it down with hot water a few times and drained it, then refilled it a couple days ago. I've been doing the dichlor-then-bleach method like before. Seems that the chlorine isn't being consumed really quickly like before, which is good! I dosed once a day and the 2nd day was like 14 FC so I was super surprised that it wasn't used up like before! Here's to hoping it's all nice and clean now!
