Help… bright yellow film on sides of hot tub. Can’t get water balanced and ready to list on Craigslist :(

[TraceyM]

A few weeks ago we used the Ahhsome purge and drained and cleaned the plumbing.  We are newbies and this is our first drain.  Our refill was sparkling clean. We tested chemicals and everything was in range, which all seemed to easy.  In followed the 3 step Bromine Instructions. I should mention this is a 2nd home where the tub is located so we are typically only here on the weekends.  The first time I came back, it was showing real high PH. We added borax and it seemed to bring the numbers down.  The following week we came back and the TA was super high as well as the PH.  I added muratic acid to lower the TA (based on pool calculator).  TA went a little lower but PH was over 8.0.  We came back this week, opened the tub and the water is yellow.  I aerated tub before testing water and we have a yellow film all over the sides that is very difficult to get off.  I am spraying the Ahhsome product to try and wipe it off.  I have not tested the water as I am going to drain the dang thing again. I added Ahhsome to the tub again, aerated for 5 cycles and am draining as I type.  Once I get tub drained, I gotta work on getting the slime off the walls.  What is it-algae? Biofilm?  Am using the right stuff to clean it (Ahhsome spray?) 

 

Once I get it cleaned, I will refill and try again.  If not, anyone interested in a brand new hydropool, lol.  I wish I knew how difficult this was going to be before spending all that $ on a headache that we have not been able to use since the drain!  Change my mind….

[waterbear]

20 hours ago, TraceyM said:

it was showing real high PH. We added borax and it seemed to bring the numbers down

Impossible, borax will raise pH, not lower it. How much did you add? Are you still testing with the K-1005? 

20 hours ago, TraceyM said:

The following week we came back and the TA was super high as well as the PH. !added muratic acid to lower the TA (based on pool calculator)

TA will not rise on its own. It was probably the results of the borax you added previously. Borax has minimal impact on TA when compered to the sodium carbonate sold as pH increaser but it will sill cause a rise in the TA.

How much acid did you add? How many gallons is your spa? You CANNOT add all the acid at once since it will often lower the pH dangerously low and can cause damage to the pump, heater, and other parts and can cause elemental bromine to form in the water.

Read this to properly lower TA and to explain what happened when you added all the acid at once. It's the ONLY way that works!

https://www.poolspaforum.com/forum/index.php?/topic/28846-lowering-total-alkalinity-howto/

Read this for basic info on TA and pH.

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

TA will change with pH and the pool calculator is not an accurate way to determine the amount of acid to lower pH since it can cause a very low pH conditions. Acid needs to be added in small increments with aeration between additions to lower TA. I suspect the very low pH you created cause elemental bromine to form in your tub. Get some sodium thiosulfate (photographer's hypo) from a photo store that sells darkroom chemicals or from an online retailer such as Amazon, Walmart (yes, they have it online only, The Chemistry Store, or a pool store (sold as a chlorine neutralizer). Get it in powdered form, either anhydrous or pentahydrate form, and dissolve 1 tablespoon in a pint of warm water and spray on the stain and let it sit for about a minute to see if it removes it. Rinse well and drain again before refilling or the thiosulfate will neutralize any sanitizer you add until it is depleted. The stain is similar to an iodine stain since they are in the same chemical family, along with chlorine and fluorine.

21 hours ago, TraceyM said:

 The first time I came back, it was showing real high PH

21 hours ago, TraceyM said:

TA was super high as well as the PH

21 hours ago, TraceyM said:

TA went a little lower but PH was over 8.0.  We came back this week, opened the tub and the water is yellow.

It sounds like your floater might be open too much and is keeping your bromine levels too high . What was your bromine reading when you tested high pH? If it was low or nonexistent I suspect the DPD test in your K-1005 bleached out because of high bromine levels (which is why I prefer the FSD-DPD test in the K-2106 and k-2006 since it does not bleach out at high sanitizer levels up to about 40 ppm for bromine or 20 ppm for chlorine, you can buy a stand alone FAS-DPD test kit from Taylor Technologies, which will essentially convert your kit to a K-2006 (only the pH test would be different, the one in the K-2006 had better precision).

You can also dilute your sample before testing. Dilute 1 part spa water to 1 part distlled water (tap water can contain chlorine which will change your results), test the diluted sample and multiply the results by 2 to get your sanitizer reading. If it is at or above 20 ppm (bromine scale) the you pH test will not be accurate.

The reason I ask about sanitizer levels is high sanitizer levels (above about 10 ppm) WILL cause the pH test to read high since it will convert the phenol read indicator into bromphenol red which detects pH between 5.2 - 6.8 which means that if your comparator read that the pH was 8.0 or above  all you really know is that the pH is 6.8

IF you have a way to measure 50 ml of water you can add 1 drop of reagent R-0007 (sodium thiosulfate) to the 50 ml sample, fill the pH comparator with the sample, and test again. If you still get the very high pH reading you will need to wait for the sanitizer to drop before testing pH.

21 hours ago, TraceyM said:

What is it-algae? Biofilm?  Am using the right stuff to clean it (Ahhsome spray?) 

I suspect it is a stain from the elemental bromine that formed due to very low pH in your water. Keep in mine that I have not tested your water nor observed it or your tub or the stain so I am basing this on my knowlege of chemisty (not just poo/spa water chemistry).

Is the Ahhsome spray removing the staining? If not try the sodium thiosulfate, it's not expensive.

21 hours ago, TraceyM said:

Once I get it cleaned, I will refill and try again.  If not, anyone interested in a brand new hydropool, lol.  I wish I knew how difficult this was going to be before spending all that $ on a headache that we have not been able to use since the drain!  Change my mind….

Don't give up. I am here to help. If need be I will walk you through it again. It's really not that hard and you have been though some mistakes that you certainly won't repeat. Read my answers a few times since there is MUCH information in here explaining some of the testing "errors" you encountered. Most of the information I proved about testing came from the Taylor Technologies website regarding DPD testing and pH testing.

[waterbear]

Your attached videos do not play. I suspect they might be too large.

[TraceyM]

Okay so hot tub is purged again and emptied.  I have refilled.  No chemicals added yet.  No aeration or heat yet. My numbers are:  TA 100; PH 6.8; Calcium hardness is 100.  Based on the 3 step Bromine method, I should lower my TA first? Dumb question-how do I lower it and test when I can only start with 1 drop ppm which is always going to start at 100?

[RDspaguy]

On 9/1/2023 at 3:02 PM, waterbear said:

TA will not rise on its own.

Aeration.

On 8/31/2023 at 5:09 PM, TraceyM said:

work on getting the slime off the walls.

Slime? It's important to be clear. If it is slimy/slippery it's a growth. If it's dry or rough it's scale (calcium precipitation from high ph/alk). If it's sticky I have an idea what it is.

Does it have a sharp, astringent odor?

[waterbear]

13 hours ago, RDspaguy said:

On 9/1/2023 at 4:02 PM, waterbear said:

TA will not rise on its own.

Aeration.

Aeration raises pH, not TA. Adding bicarbonate or carbonate raises TA, Acid lowers TA Aeration raises pH by gassng off CO2 so TA does not rise with the pH rise.

[waterbear]

4 hours ago, RDspaguy said:

Does it have a sharp, astringent odor?

I think we are on the same page, elemental bromine from very low pH.

[RDspaguy]

On 9/2/2023 at 11:19 PM, waterbear said:

I think we are on the same page, elemental bromine from very low pH.

Nitric acid in the ozone tube from an undersized mazzei. Gets sucked in, coating everything in sticky yellow gunk and foaming like crazy. 

You know darn well I'm no chemist my friend. Elemental bromine? You give me too much credit.🫡

[waterbear]

On 9/6/2023 at 12:42 AM, RDspaguy said:

Nitric acid in the ozone tube from an undersized mazzei. Gets sucked in, coating everything in sticky yellow gunk and foaming like crazy. 

Missed that the tub had ozone. You're probably right!

On 9/6/2023 at 12:42 AM, RDspaguy said:

You know darn well I'm no chemist my friend. Elemental bromine? You give me too much credit.

You hold your own pretty well! Elemental bromine can form when the pH drops very low (which it looks like it did). It can color the water yellowish to brown and can stain, similar to Iodine. Has a sharp odor similar to chlorine and iodine. Toxic, similar to chlorine and iodine.

[TraceyM]

Okay so what does Elemental Bromine mean and what do I do about it???

We left on Sunday and everything was great. TA below 100; PH was 7.6; Calcium was 100 so I added a small amount (1/3 cap full); Bromine was 6.  We arrived today and lifted cover- water has a yellow tinge to it AGAIN.  I have aerated several times and my PH is golden yellow-below 6.8. TA is still at 100; Bromine is 8.  Other than the starter bromine pack and the bleach, nothing else was ever added.  What do I do now???

[TraceyM]

***Nitric acid in the ozone tube from an undersized mazzei. Gets sucked in, coating everything in sticky yellow gunk and foaming like crazy***

 

The tub has ozone.  What does the above mean and how do I fix this???

I just retested the Bromine and previously posted at 8 but it is over 10pm.  Help please as this is my 2nd refill!

[waterbear]

You can't test pH or adjust it when sanitizer is over 10 ppm. Take out the floater and let the bromine drop (running the tub uncovered will help). In the mean time get a box of 20 mule team borax from the grocery story. Add 1/2 cup per 200 gallons. Wait for sanitizer to drop below 10 ppm, test pH and TA, and we'll take it from there. As for elemental bromine, it will fix itself once the pH is right. As far as the nitric acid, it will also fix itself once the pH rises but to keep it from reoccurring I would defer to @RDspaguy since his expertise is equipment repair. Let's see what he has to say.

[waterbear]

Don't worry, it's all good. You've gotten over a pretty steep learning curve very quickly. You now know that you can't test pH or TA when sanitizer is high and if your sanitizer reads low or nonexistent there is a chance your DPD test has bleached out and is reading low so dilute your sample with distilled water 1:1 and retest, multiply test results by 2 to get reading. (OR just get the Taylor stand alone FSD-DPD test kit. Much easier to use, no color matching. You are looking for it to go from pink to colorless as you add drops and count the drops. It will also handle a much higher sanitizer range than the DPD test and give you accurate results with NO dilutions.

Once the bromine drops don't put the floater back until we get the pH, TA, and CH in line. If you could post a pic of your bromine floater it would help, Some are totally useless as far as adjustments go. I recommend the Pentair 335 floater that holds 1" bromine tablets . It looks like this and is VERY adjustable. It's often sold unter the Rainbow brand, which is one of Pentair's brands.

 

 

 

[RDspaguy]

14 hours ago, waterbear said:

As far as the nitric acid, it will also fix itself once the pH rises

In my experience it will not and must be cleaned and have the mazzei, tube, and check valve replaced. And this stuff is extremely sticky and thick. 

A dealer I used to work for had this problem with a batch of new tubs when the manf switched to a "high output CD ozonator" but were still using the mazzei for the old style. Went round and round with them since we got the first shipment of these and so nobody else was having issues yet. They said it was chems and refused warranty until I sent them a clogged mazzei tube. Bigger (higher flow rate) mazzei and no more trouble. In theory, an extended flow restriction (greater than the mazzei itself) in the ozone return line could also cause this.

18 hours ago, TraceyM said:

The tub has ozone.  What does the above mean and how do I fix this???

Post pics of equipment area and I'll direct you.

[TraceyM]

Added the Borax and aerated.  PH now 7.6  Yellow water is now clear too!  Tested Bromine again after leaving open and aerating for some time and Bromine is down to 2.  Is that normal for it to drop that much? (The Bromine floater we have looks just like the ones you posted)

[TraceyM]

RDspaguy- our tube is a hydropool Signature 695.  I have already left the house but I can take a picture and repost tomorrow when I go back up there 😉 Is this something I need to call the dealer and make a service request for?