Need Water Maintenance Suggestion

[nizman]

I got my first hot tub in 2005 and started with bromine.  Had no issues for the first 3 years then I suddenly developed an itch on my legs after using the tub.  No one else in the family had any issues.  After consulting with my dealer and a year of trying a bunch of things, we finally settled on a switch to Baqua Spa.  While it solved my itch problem, I hated the product.  It had a rather unpleasant smell and if breathed while the jets are on, it burns your lungs.  Sometimes a nasty gunky film would form on the waterline.  Nevertheless, I was a (somewhat) happy soaker. 

Bought a new tub in 2022 and the dealer sold us on the Frog system after I told them of my itch issues.  While it's somewhat easy to use, I'm getting black mold above the waterline even when the test strips say there's plenty of sanitizer.  It's also freakishly expensive!  I did try using the Baqua Spa (they now call it Sirona), but it was a big fail.  The gunky film formed almost immediately and was near impossible to clean up. 

I had a doctor look at my legs and he said it was eczema and would likely itch in hot water in general (shower, bath).  

So I'm looking for a new water care method.  I've been reading about the Dichlor/bleach method and the 3 step bromine.  Some other things about my situation that might influence the decision:

• Tub is used about once per week and I'm typically the only one that uses it.
• I travel for my job and can be gone for a week at a time.  While I can trust the family to add something to the tub on occasion, I wouldn't expect them to use a test kit.
• Speaking of test kits, I own a Taylor 2005 and only use it for new water startup.  I've had it for 10+ years and only use it to test TA, calcium, and pH. Will this kit work for the chlorine or bromine methods?  I've never used the chlorine testing reagents.  I'm guessing I might need to buy fresh ones?
• I have nasty well water.  My softened water has a TDS of 1500.  Out of the tap, the TA is typically 200+.  Takes most of a day using ph down and agitation to get the TA to acceptable.  Also have to add a bunch of calcium.
• Lately I've been buying water rather than deal with mine.  It has a TDS of <300, TA, pH, and calcium are already in balance, just add chemicals.  Only issue here is, it costs $300!

With that, which method might be best?  I've read a bunch here that suggests chlorine might be better with my eczema issue, but bromine might be less maintenance if I'm not around.  One last question, with the black mold issues, I picked up some Ahhsome and plan to do a purge.  Do I need to need to super-chlorinate after or should the Ahhsome be enough.  I noted that the super-chlorination step requires the water be balanced first which, as noted, is difficult for me if I use my water. 
Thanks!

[waterbear]

19 hours ago, nizman said:

I'm getting black mold above the waterline even when the test strips say there's plenty of sanitizer.

No, there isn't. Often the reduced sanitizer recommended for "Mineral" (metal ion) system such as the Frog and Nature2 is depleted quickly and can lead to problems such as you describe. DId you have the bromine based or chlorine based Frog system? Also, strips are not the most reliable. If you are using Frog@ease, which uses a proprietary form of chlorine than you must use their strips since their chlorine will test as combined chlorine.

19 hours ago, nizman said:

I did try using the Baqua Spa (they now call it Sirona), but it was a big fail.  The gunky film formed almost immediately and was near impossible to clean up. 

Did you drain, refill, and clean your filters before you added the biguinide sanitizer (generic name for Baqua, SoftSoak, etc.). If not it will immediately form BaquaGoo! You can convert a chlorine or bromine system without draining but it requires a lot of chlorine or sodium percarbonate to do so.

20 hours ago, nizman said:

had a doctor look at my legs and he said it was eczema and would likely itch in hot water in general (shower, bath).  

IF you have eczema then it's the hot water that's causing the problem and the choice of sanitizer will probably have little impact.

20 hours ago, nizman said:

I've read a bunch here that suggests chlorine might be better with my eczema issue, but bromine might be less maintenance if I'm not around.

Bleach baths (at around 25 - 50 ppm) are used to treat Exzema in children. Chlorine does require daily or almost daily additions, 3 step bromine, once everything is adjusted, can go longer without intervention. However, as I said, it's probably the hot water that's causing the problem for you.

20 hours ago, nizman said:

While I can trust the family to add something to the tub on occasion, I wouldn't expect them to use a test kit.

You cannot dose a tub unless you know what the current level is and from that determine how much of a specific chemical is needed. Period. End of Story.

20 hours ago, nizman said:

I own a Taylor 2005 and only use it for new water startup.  I've had it for 10+ years and only use it to test TA, calcium, and pH. Will this kit work for the chlorine or bromine methods?  I've never used the chlorine testing reagents.  I'm guessing I might need to buy fresh ones?

If your kit is over 10 years old you need ALL new reagents! My suggestion is to just buy a Taylor K-2006, which has a better test for chlorine/bromine than the k-2005. All other tests are identical. If you are going to use bromine you only need to test free chlorine and then multiply the result by 2.25 to get a bromine reading and you do not need to test CYA in a bromine system. The FAS-DPD testing method in the K-2006 does not bleach out at high sanitizer levels like the DPD test in the K-2005 and can directly test much higher (shock level) sanitizer without having to dilute your test sample with distilled water.

20 hours ago, nizman said:

Will this kit work for the chlorine or bromine methods?

The K-2005 was designed to test both chlorine and bromine. T

 

20 hours ago, nizman said:

My softened water has a TDS of 1500. 

TDS is a bogus measurement and means nothing. Most of the TDS in your case is most likely sodium and 150   0 ppm is way below what most salt water chlorine generators need to function.
 

20 hours ago, nizman said:

Takes most of a day using ph down and agitation to get the TA to acceptable

I've seen it take a few days when TA is extremely high so yours is not that bad.

20 hours ago, nizman said:

Also have to add a bunch of calcium.

If you are filling with softened water you will. You want your CH around 130 to 150.

20 hours ago, nizman said:

Lately I've been buying water rather than deal with mine.  It has a TDS of <300, TA, pH, and calcium are already in balance, just add chemicals.  Only issue here is, it costs $300!

TDS is a bogus measurement, ignore it. What the the CH and TA measurements of the water you are buying? TDS  is a measurement of all the ionic species in the water so you combined CH and TA should be well under 300 ppm.

 

20 hours ago, nizman said:

I noted that the super-chlorination step requires the water be balanced first which, as noted, is difficult for me if I use my water. 

IF you get the TA down to  150 ppm or less and the calcium to 130 it should not take that long. Then super-chlorinate. IMHO, balancing the water first before super-chlorinating is probably not really necessary as long as you balance it once the FC drops to normal levels or you dump the water and fill with your bought water. @Ahhsomeguy, care to jump in?

[nizman]

1 hour ago, waterbear said:

22 hours ago, nizman said:

'm getting black mold above the waterline even when the test strips say there's plenty of sanitizer.

No, there isn't....

Totally agree.  This is the reason I want to dump the Frog.  I don't trust it and the test strips lie.  My point was, the strip says there's sanitizer when there isn't.
 

1 hour ago, waterbear said:

Did you drain, refill, and clean your filters before you added the biguinide sanitizer (generic name for Baqua, SoftSoak, etc.).

Yes, in fact, I drained, refilled, drained, refilled (to ensure everything was out of the pipes).  But I was doing this before I knew that my leg itch was eczema and likely not because of the sanitizer I was using.

1 hour ago, waterbear said:

If your kit is over 10 years old you need ALL new reagents!

While the base kit is old, the reagents I regularly use are not.  The reagents I have for testing  pH, TA, and CH are all fairly new.  Not opposed to buying a new kit, but if I only need to buy a few reagents to test beyond what I have (CYA, etc.) that might be more cost effective if my existing kit will still work.

1 hour ago, waterbear said:

TDS is a bogus measurement and means nothing. Most of the TDS in your case is most likely sodium and 150   0 ppm is way below what most salt water chlorine generators need to function.

Good to know.  My dealer always made a big deal out of it and said I needed to change water more frequently due to this high TDS. 

Quote

What the the CH and TA measurements of the water you are buying? TDS  is a measurement of all the ionic species in the water so you combined CH and TA should be well under 300 ppm.

CH=130, TA=150.  As noted, requires little adjustment. 

1 hour ago, waterbear said:

...balancing the water first before super-chlorinating is probably not really necessary as long as you balance it once the FC drops to normal levels or you dump the water and fill...

Can you clarify this?  If I did the super-chlorinating step, I was assuming I'd drain and refill - either with my water or the purchased water.  I wouldn't want to try and balance this super-chlorinated water.  Another question on this - if I did this step, it would easier if I filled the tub with water straight from the well instead of softened water.  But there's all sorts of extra things in that water (minerals, iron, etc.).  Could I use well water for this disinfectant step?

 

 

[waterbear]

18 minutes ago, nizman said:

but if I only need to buy a few reagents to test beyond what I have (CYA, etc.) that might be more cost effective if my existing kit will still work.

Get the Taylor Technologies K-1515 FAS-DPD test kit. That, combined with the CH, TA, pH with acid and base demand, and CYA tests in your K-2005 will give you the equivalent of the K-2006 for a lot less money. You probably won't find it locally but It's available on Amazon and several online pool/spa supply stores.

 

32 minutes ago, nizman said:

My dealer always made a big deal out of it and said I needed to change water more frequently due to this high TDS.

You need to change the water every 3 to 4 months. Period. If you are using dichlor exclusively that time might be sho9rter because of high CYA but it has nothing to do with TDS.

34 minutes ago, nizman said:

CH=130, TA=150.

CH is perfect., TA requires a LOT of adjustment!
TA is way too high. Should be 50 to 70 ppm for best pH stability. The constant aeration of the water from the jest will outgas CO2 and cause pH to rise and the higher the TA the faster this will happen.

https://www.poolspaforum.com/forum/index.php?/topic/52522-some-truths-about-ph-and-ta/

https://www.poolspaforum.com/forum/index.php?showtopic=28846 (this post explains the chemistry behind this in layman's terms)

39 minutes ago, nizman said:

I wouldn't want to try and balance this super-chlorinated water.

Why t?t. Just let the chlorine drop below 10 ppm before adjusting pH, TA, and CH. If you are using bromine then add the sodium bromide and you won't need to shock again. The remaining chlorine in the tub will activate your bromide reserve.

42 minutes ago, nizman said:

Could I use well water for this disinfectant step?

Maybe. Depends on how much iron and other metals are in the water. If adding a high dose of chlorine causes the water to discolor then it could result in metal stains depositing on the tub. Iron causes yellow water, copper causes green, manganese causes purple.  Sometimes iron and copper can get confused if the hot tub has a blue gelcoat. Yellow water against a blue hot tub shell will make the water look green and you might think you have copper in the water when it's really iron. High calium (very hard water) should not be a problem, not should high TA.  but that also depends on just how high.

 

 

[nizman]

On 3/21/2025 at 4:00 PM, waterbear said:

Get the Taylor Technologies K-1515 FAS-DPD test kit.

I'm thinking of going the Bromine route.  Is there a better kit that would test for bromine directly (like what would be in the k-2106) or would it be best to get this kit and do the "multiply by 2.25" thing?  I poked around the Taylor site but there are a ton of options.  Thanks!

[waterbear]

The K-2106 tests bromine with a precision of .5 and 1.25 ppm directly and also tests pH with acid and base demand, TA, and CH (exactly the same tests as in your K-2005). It does not include the CYA test. The K-2006 with chlorine has a precision of .2 and .5 ppm. This depends on the size of the sample with a 10 ml sample giving the higher 1.25/.5 precision and the 25 ml sample giving the .5/.2 precision. I recommend using a 10 ml sample for chlorine and a 25 ml sample for bromine.  If you use the K-2005 or the K-1515 the multiplication by 2.25 will give you a precision of .45 for the 25 ml sample and 1.3 for the 10 ml sample, essentially same as the K-2106.  You can just double the reading and you will be in the ballpark if multiplying by 2.25 is too much. In fact, this is what Taylor does on the K-2005 comparator. If you look at it you will see the bromine scale is just double the chlorine scale.

You want a kit with the FAS-DPD testing method for chlorine or bromine.  This means either the K-2006, K-2106., or adding the K-1515 on to your K-2005 which makes it a K-2006.

Your least expensive option is adding on the K-1515, which is what I would do unless your current K-2005 is in bad shape or missing components. Even in that case it would probably be cheaper to just replace the missing or damaged components. Just realize that you cannot use the K-2106 for chlorine. It is bromine only.

 

[nizman]

Update on my progress.  I have my tub setup for bromine and I'm testing with my K-2005 + the K-1515.  My tub has never looked better.  But... I can't use it.  I'm getting a new itch problem above and beyond my eczema.  Here's the detail:

• Per the 3 step instructions, got my TA, CA, pH in balance, added sodium bromide and activated it with liquid bleach. Waited for the bromine to get below 10 ppm than added my tablets.
• Was able to use the tub twice in two successive nights with no issue. Tested prior to each use and was in range (I didn't write these numbers down, but I don't recall seeing any issues).
• On the third use, everything was still looking good, but about 3 hours after the soak, I started itching from head to toe - back, legs, and especially my mid-section (if you know what I mean) were on fire. This itch was all over and not just in my eczema areas.  Numbers were: TA=60, ph=7.4, CA=140, Br=4.
• I waited for over week to recover before trying the tub again.  In this time, I wondered if the issue was doing the initial shock with bleach.  On the next shock I used MPS.  When I tried the tub again, I got the same itch issue.  For this soak, TA=50, pH=7.6, CA=140, Br=4.5.
• In the month I've been running on bromine, family and friends have been using the tub with no issues.

As noted, my tub has never looked better so I really want this to work.  But I'm the primary user of the tub so if I can't get this figured out, I need to try something else.  My questions:

• Is there something I should be doing different?  I get there are possibly variables I'm not mentioning or unaware of.
• Is there a potential that the chlorine method would work better?  I really like the level of effort associated with maintenance for the bromine system.  But I would also like to use my tub on a regular basis.  Willing to move to chlorine if there's a chance it will work.
• As noted at the beginning of this thread, I was a successful biguinide user for 12 years.  While I hated using it, I was also able to use my tub!  If I have absolutely no choice, any suggestions on how to be the most successful with this method would be welcome (ie, best product, best water balance ranges, ongoing maintenance suggestions, etc.).

[waterbear]

On 3/21/2025 at 12:58 PM, waterbear said:

On 3/20/2025 at 4:00 PM, nizman said:

had a doctor look at my legs and he said it was eczema and would likely itch in hot water in general (shower, bath).  

IF you have eczema then it's the hot water that's causing the problem and the choice of sanitizer will probably have little impact.

 

[nizman]

Understood... this itch is different.

Thanks.

[waterbear]

23 hours ago, nizman said:

• r this soak, TA=50, pH=7.6, CA=140, Br=4.5.
• In the month I've been running on bromine, family and friends have been using the tub with no issues.

water balance looks perfect and you are the only one reacting.

23 hours ago, nizman said:

  On the next shock I used MPS.

MPS is a known sensitizer, avoid it.

23 hours ago, nizman said:

Is there a potential that the chlorine method would work better?

Only way to know is to try it. You will need to completely drain and refill. You cannot convert from bromine to chlorine any other way. You can convert chlorine to bromine by adding sodium bromide. but not the other way.

If all else fails you can try biguinide again. If that doesn't work it's from the hot water. Some people do develop a reaction to hot water that can manifest as an itching or painful rash.