[Black flakes in hot tub]

2 hours ago, waterbear said:

A spa is not hard to maintain but it does require some attention. 

You can feel free to ignore my above questions. A brief search on the topic sent me to a post you wrote in 2021 (3 step bromine guide) that essentially answered all the above already. You even mentioned borate and that chlorine spas basically require daily attention whereas bromine spas are much more forgiving. Which explains why we are having so many issues maintaining our current chlorine spa. So it sounds like switching to bromine is definitely in our best interest given our relative inability to perform daily maintenance on our chlorine spa. The only question I have now is if I can simply switch to bromine now using your guide (establish a bromine reserve, etc) or if I have to wait a bit for my chlorine level to come down? I would assume we can just go ahead and establish the bromine reserve now since the current chorine level will only help sanitize while this is established, or would having a current chlorine level interfere with the first step and jump us to the "shocking" step before we are ready?

 

Again, thank you for your advice and I apologize for taking up so much of your time over the last few days. You have been most helpful and you are greatly appreciated. 

[Black flakes in hot tub]

1 hour ago, waterbear said:

I gave you my advice. If you want to continue to use trichlor in your spa be my guest but I can offer no other help. Perhaps someone else can.

WOW! Lots of excuses as to why you cannot care for your spa. Perhaps your wife is right. A spa is not hard to maintain but it does require some attention. As I said, I gave you my advice but it's your spa and you can do whatever you want with it but you obviously have some problems going on so perhaps you should rethink owning a spa.

It was not my intention to be difficult and I am surely not taking your wisdom or advice for granted. I apologize if I came off that way. I do NOT want to continue to use Trichlor, but I do need to find a happy medium with maintaining a safe/clean spa and our busy lifestyle. I assumed I couldn't be the only spa owner who takes vacations or is too busy to show daily love to their spa, so I also assumed there was some happy medium out there for cases like mine. Especially in the middle of winter in Michigan it is literally hazardous to stand out in negative temps testing water every day (yet another excuse I guess). I leave for work before daylight and come back after dark. I spend my days in a hospital caring for my community and I guess I was hoping for some non-judgemental help in maintaining something that is therapeutic for my body, but also entertains my children. The fact of the matter is that I am not getting rid of the spa for the above reasons (although it has crossed my mind with some of the issues we've had), but in the same breath I am unfortunately too busy to properly maintain a chlorine spa per all your very helpful information. Since you have pointed out that having a bromine spa and a chlorine pool should not be an issue, I wonder if switching to bromine be the fix I am looking for (especially since I have previously maintained a bromine spa without any issues while facing the same busy schedule). If you don't mind just answering a few more questions I would greatly appreciate it. PS I fully intend to purchase the Taylor kit you mentioned to more accurately test not just my spa, but our pool as well. 

1) Do bromine tablets in a floater pose any of the same threats to my spa as Trichlor? (keep in mind I fully intend to test pH, TA and bromine levels at least once or twice a week using the proper test kit you have mentioned). 

2) If I switch to Bromine (likely a combination of tablets and granular), would I want to use MPS to help oxidize at that point, or add granular bromine to "shock"? - I will do my due diligence and search these forums for proper maintenance regimens for bromine spas as I'm sure you have enlightened people on this already, so if you choose not to answer this I would understand. 

3) Can I continue to use boric acid in the spa if I switch to Bromine? I really like the way it made my spa feel (and I believe I took this advice from a prior post/comment from you, so thank you. 

I would like to reiterate that I greatly appreciate all your help and advice. I know it's not often that you have experts willing to help others for free and that sentiment is not lost on me. Especially since the people that sold me the spa have lead me down a completely incorrect path that has possibly lead to damage to my spa (o-rings and seals from very low pH) and the local spa/pool store that is open year round is less than willing to give free advice even though I buy my spa chemicals from them. 

[Black flakes in hot tub]

1 hour ago, waterbear said:

Trichlor is way too acidic to use in a hot tub!  HOt tubs have a very small water volume compared to a pool and it is very easy for chemical parameters to change quickly! Most spa manufacturers will void the warranty if you use trichlor. Also, trichlor adds 6 ppm CYA for every 10 ppm  FC added while dichlor adds 9 ppm CYA for ever 10 ppm FC added. Overstabilization will happen quickly. A spa should not be over 30 ppm CYA! I have a suspicion about what these flakes might be.

- the only problem is that I work 84 hours a week in the hospital and don't have time for the daily maintenance required for using a bleach only method (once 30 ppm CYA is reached using stablized chlorine). My wife would likely much rather get rid of the spa than have one more thing to manage around the house (and I wouldn't blame her with being the primary caretaker for our children). We also tend to travel whenever I get time off, and I doubt we can get someone out here every day to add liquid bleach to the spa to keep the sanitizer at an appropriate level, which is why we use Trichlor primarily when we travel, but tend to keep 1 small 1 inch tab in the floater. 

- oddly the floater and trichlor came with the spa from the company who sold it to use brand new. 

Exactly which Taylor kit do you have? Are you using strips to test CYA?. My guess is you are and you have a basic Taylor kit that does not test CYA, and probably uses DPD for chlorine testing, based on getting a FC of 5-10 ppm (which is not enough precision to be useful for anything!)  Get a Taylor K-2006 and be done with it and stop using trichlor and only use dichlor unti your CYA reaches 30 ppm and no higher then switch to bleach. Keep your TA between 50 to 70 ppm and your pH between 7.6-7.8 and do not lower it until it goes above 7.8 for best pH stability. Shock when CC is 1 ppm or higher, don't use MPS. You can add 50 ppm borate for even better pH stability along with the other benefits of borate. I prefer using boric acid since it does not require pH adjustment like borax.

- It sounds like I likely have the basic Taylor kit then. No CYA. I use the strips for CYA and generally for FC as well since they seem to always be on par with the Taylor kits FC reading. 

- I actually did add borates this time around and will continue to use them. I love how soft the spa feels and the lower chemical usage is a big plus too. 

 

I suspect the black flakes are from degredation of o rings or seals because of low pH from trichlor use. IF the skimmer is near an intake very low pH water could go directly into the plumbing while the pH in the tub reads much higher.

- if these flakes are o-ring or seal degradation, I would expect to have a problem by now given the massive amount of flakes I was seeing. Plus some of these flakes are likely far too large (very fat flakes) to be from an o-ring. I can see that the pictures I took could easily look like o-ring degradation, but they were much fatter/larger prior to the multiple purging and drainings I performed. I am not trying to argue with you at all, as I am definitely no expert, especially in hot tub mechanics. Wouldn't I expect a pump to be leaking by now if I had that much degradation of the o-rings and/or seals?

- when I say "tough" I don't mean rubber tough, just doesn't disintegrate in front of my eyes like the white mold did. But it does break down rather easily still (how I would imagine a thin film of black mold would act when rubbed between my fingers).

- on the same note I will say that when we were using two tabs of Trichlor in the floater we would get significantly low pH readings from time to time. So I can see what you are saying, because we had VERY low pH more than a few times since owning this spa. 

- if you are correct, this could also explain why I never got this issue with our old tub from our last house (bromine tub). I assume bromine tablets don't carry the same acidity or stabilization problem?

Use 6% plain, unscented laundry bleach. both are sodium hypochlorite.

- I generally have more than enough of my more concentrated pool bleach that I get for our pool. I did some calculations (using data I have found on this wonderful forum - might have even been from you haha) and arrived at roughly 1/4 cup for two bathers soaking for 30 minutes for "shock" or after each use (of my 12.5% bleach). Does this sound about right? If not, how much 6% bleach would you recommend putting in after each bathing session as described above (2 bathers at 30 minutes each in a 400 gallon spa)?

All of this brings up another question....if I by some miracle haven't screwed this tub up (bad o-rings and seals), is there really any concern with using bromine in my hot tub and chlorine in my pool? My kids love to go back in forth (especially at the beginning and end of the season when the weather is a little colder). It seems like switching to bromine would solve most of my problems with not being able to tend to this tub every day and would allow me to use pucks in the floater without worrying about my o-rings or seals. I feel like the pool is such a large area that whatever little bromine would enter from our bathing suits would likely not impact anything, but I definitely don't want to risk it if you are unsure. 

What problems should I be looking for if this is degrading o-rings or seals? I am assuming a leaking pump?

Are you saying not to use MPS at all? Or just not for "shocking purposes"? I have read that the weekly dose still helps as it oxidizes and lets the chlorine be used more for sanitization rather than oxidizing. 

[Black flakes in hot tub]

On 3/20/2024 at 12:27 PM, waterbear said:

IF possible, post some pictures of the black flakes. Sounds like green algae, which often looks black. Pictures will help. Causes are chlorine too low or CYA (stabilizer) too high.

- just soaked in the spa with my daughter and there was a few flakes of varying sizes. Light brown to dark brown/black. They actually do NOT disappear when rubbed between my fingers (as I previously incorrectly described) like the previous white mold, but do shred/ball up. They seem "tougher" than the white mold biofilm I had previously. Sometimes so tough it almost seems tar-like after I rolled between my fingers, but not always. 

- for completionism and accuracy of information I checked the FC and CC using my Taylor kit and the strip is indeed accurate with 5-10 ppm free chlorine (closer to 5 than 10) and zero CC. Also checked the CYA and it is between zero and 50, closer to the zero than the 30 to 50 mark. 

- Also checked my phosphates for giggles and its between 50-125 so I will be using the "weekly dose" tonight when the filters kick on, but not high enough to be of real concern from my understanding (in the past my values were well into the 100s or even over 1k when I had issues). 

- I have attached pictures of some of the "biofilm" I'm finding today and one picture of the water to show how wonderful it looks. I also noticed that I think I see more AFTER the jets shut off and the pressure backs off and I get some bubbles from air in the line being purged. Not sure if this observation makes a difference or even if it's accurate. The other day when I made my original post, there were hundreds of these flakes ranging from very tiny to as large as you see in these pictures (sometimes a littler larger) and this was AFTER having zero (or minimal) flakes since the purge/refill. 

Thanks again folks

 

[Black flakes in hot tub]

On 3/20/2024 at 12:27 PM, waterbear said:

Waterbear, 

What form of chlorine are you using? Dichlor, Bleach, cal hypo?

- A mix of Dichlor, Tricolor (tablets in a floater) and concentrated pool bleach (that we also use in our pool - 12.5%). We generally use one trichlor tab in the floater just to give us a buffer if we aren't able to attend to the spa for a few days. Dichlor randomly or if we are out of bleach for a moment in time (our pool store is only open in the spring through fall). This combination tends to keep my CYA appropriate until it is time to drain and refill anyway (every 3-6 months generally). 

What is your stabilizer (cyanuric acid) reading?

- currently minimal because I JUST purged and refilled the tub multiple times and my CYA slowly climbs over a period of months from the use of 1 Trichlor tab in the floater (sometimes two if we are going out of time for a week or so - we also typically have someone check on the tub and feed our fish, etc) and the occasional dichlor use. 

How are you testing your water?

- A mix of Aquacheck testing strips (purely for the FC and CYA readings) and my Taylor dropper style test kit (which I love) for everything else. 

Start by posting a full set of test results (FC, CC, pH, TA, CH, CYA)

- FC is 5-10 range, sometimes 10+ for a bit after a shock, this is using the test strip which I have found to be accurate over the years (for the FC and CYA levels that is, I don't trust it for much else)

- CC is unknown as I generally only check this when I have an issue or I have a strong chlorine odor (chloramines)

- pH currently 7.4, I keep it between 7.4 and 7.6 optimally, has been known to rise over a few days (likely secondary to the bleach use). In the past when we only used Trichlor/Dichlor it would typically drop over time. 

- TA is 70, plan on bringing this up a bit today. Has dropped from the 90 mark originally due to the addition of some acid for pH adjustments. My well water has absurdly high TA (like 300+) so when I fill the tub I have to use a decent amount of acid to drop this down before I adjust pH, but I have the process/amounts down at this point. 

- CH is 150, this is straight out of the hose and has typically remained extremely stable (I check before draining as well to see if it changes) since I don't use Cal Hypo

- CYA currently on the low side as I just refilled the tub in the last two weeks and only use minimal stabilized chlorine (see above)

IF possible, post some pictures of the black flakes.

- naturally after swapping out the filter again and using my skimmer net on all the visible flakes a few days ago (right before posting all this) I don't have any flakes to show you at this time (but this has occurred on and off since refilling the tub after multiple system purges - per my original message/question above, so something tells me I will be able to show you a picture soon)

Sounds like green algae, which often looks black. Pictures will help. Causes are chlorine too low or CYA (stabilizer) too high.

- we have had an algae bloom in the spa before which looked much different (we get it in our pool almost once a year when the temps get really warm). We found it was because of phosphates, which I do test for when/if I get that greenish tinge to the water or have trouble keeping my chlorine up (since the last time we had this issue we couldn't put enough chlorine in the water to get a readable level and could not figure out what was going on until we got the phosphate test kit and found out we had essentially started an algae farm in our spa and it was being fed by high phosphates). This looks like mildew/black mold, only comes out when the jets are on (like biofilm or the white mold you mentioned), we had some around the aerator knobs prior to cleaning the shell after our sanitizer levels got low (as mentioned in my very long original post). But this has since been cleaned, looks a lot like that though. 

- chlorine has not been low in over a month now and has, in fact, been high. This is also after multiple system purges and draining/refilling x3 now. For these same reasons CYA has not been elevated as we haven't used enough stabilized chlorine in the spa yet since I have drained and refilled so many times recently. 

What chlorine level are you maintaining? Chlorine level is dependent on the CYA (stabilizer) level.

- since the most recent fill we have maintained mostly a 5+ FC level, sometimes as high as 10+ after shock. It has gotten as low as 3 briefly (about a day or two) but that should still be acceptable (most people consider 3-5 normal, but I like higher levels around 5-10 for a spa - my family tolerates the higher chlorine levels just fine so I like the extra sanitizing power given the issues we've had). 

Never heard of this. Vinegar can be used to help remove mildew from hard surfaces when used full strength in a spray bottle but it is not as effective as chlorine,which is why most commercial mildew removers are chlorine. Never heard of it being used in a hot tub. and it does not play well with chlorine and can release harmful gases.

- I will avoid the vinegar then. I assumed that chlorine/bleach would be better anyway, but I also read that the chlorine/bleach has trouble penetrating the slime layer of the biofilm and vinegar does this job wonderfully. I shall avoid mustard gassing myself however haha. 

I look forward to any more advice/wisdom you can impart and thank you for your help thus far

 

[Black flakes in hot tub]

I have a relatively new 400 gallon spa that we bought about 2 years ago. We use chlorine because we also have a chlorine pool and don't want to risk mixing of chlorine and bromine. At one point we had what looked like extensive amount of shredded white tissue or toilet paper floating throughout the spa when jets were on. This is when I first learned about biofilm. After cleaning/purging the spa with Ahh!Some cleaner, draining, cleaning the shell thoroughly and refilling we thankfully fixed that problem. That was about a year ago or more. Months ago we went on vacation and the person watching our house completely forgot about the spa care aspect we were paying them for, so chlorine levels were at zero for a few days. Weeks later we noticed biofilm (or that is my best guess) again, except it was black flakes (slimy that seem to disappear when rubbed between fingers - similar to the white version). I assume this is a black mold biofilm? We have not been nearly as lucky getting rid of this as we did the white flakes. I have used the Ahh!Some cleaner again, drained, cleaned and refilled the tub, only to find a bunch of black flakes again the following day. I read that it can take up to 3 applications of the Ahh!Some before you truly clean/purge the pipes. So the following week I used two more doses of Ahh!Some cleaner, draining, cleaning and rinsing the shell and refilling with clean/cold water in between each application (while running the jets to purge sufficiently - and even taking turns turning off jets on one seat at a time to increase the pressure and force this stuff out) before draining again. I noticed a few more specks at first but they seemed to be gone or at least not problematic (we might see one or two flakes - if any - about the size of the head of an eraser on a pencil or smaller even). That was last week...I was happy because it seemed my hard work, high water bill and hundreds of dollars in chemicals was worth it. We have kept our chlorine high (has not dipped at all) and made sure our water parameters are in check and shock with both chlorine and non chlorine shock after every use. We run the jets on full with the aerator wide open every couple of days at least while we check/add chemicals. All jets are open as well (as we believe have multiple closed jets for extended periods led to our first white biofilm problem).

Today the kids, my wife and myself enjoyed a soak and once the jets kicked off after its normal 15 minute cycle we unfortunately noticed a ton of black flakes of various sizes again. We had been swapping and soaking the filter every couple of days after draining and refilling (we have two filters we swap out). One of filters was even brand new and fresh out of the package. We left the current filter in for the last week since I was at work all week. I did just swap it out with the filter that was soaking in filter cleaner again (which looks pristine). We don't have any headrests or any other external black/rubber components that could be causing this. I am about ready to sell this spa because it is becoming so frustrating, but we live in Michigan so my kids (and my joints/back) really enjoy the spa, especially during the colder months. I have a few questions that I was hoping some experts could help me with as my local spa dealers/shops have been less than willing to help. 

1) Is the spa safe to use for my family as long as we maintain a chlorine level? Or do these black flakes present a health hazard to us? I have heard both. I have heard biofilm itself isn't really dangerous, but only when it prevents you from maintaining a proper sanitizer level (as it is used up trying to kill the biofilm) and opens us up to unsafe swimming/soaking due to the risks associated with low/zero sanitizer. I have also heard that the biofilm/mold itself is dangerous even with proper or high sanitizer levels?

2) What more can I do to get rid of this stuff? I can't just keep purging/cleaning/flushing the system, cleaning and refilling this spa because (a) it doesn't seem to make a difference and (b) it is time consuming and costly. I have read that running white vinegar will take care of the biofilm (but you would obviously need to adjust pH after given the high acidity), is this safe for the spa? Does it actually work? I have also heard to super chlorinate or keep chlorine high for weeks and/or do frequent filter changes (which we are basically doing (not SUPER chlorinating, just keeping it high at like 5-10). 

3) Depending on the answers to the first two questions...do I even need to worry about getting rid of this? My water is beautiful (except for the black flakes/specks - which haven't been seen in mass until today), we have no issue at all maintaining the water parameters and sanitizer levels like we did with the last two biofilm issues (the original white one and the beginning of this black one). This clean water and zero issues maintaining water parameters make me wonder if I really have to worry about this?

4) Do spa "enzymes" help at all for this particular problem?

Thanks ahead of time for any help/insight you guys/gals can provide. Believe it or not I am an experienced spa owner, but my prior spa was Bromine and we NEVER had this issue in the 5 years I lived at that house even when we were neglecting the spa and sanitizer levels got very low for extended periods (that was a very old spa and a very old house haha). We moved and did not have a spa the first few years in our new home and I decided to change that a few years ago and am starting to regret my decision sadly. 

- AJ -