Brown flakes in hot tub

[aguywithaspa]

Measured pH again, still as red as it gets at 8.2+. My faucet water is also that high. I don't know if that's normal or not.

The 1.5 cc is concerning - raise to slam level
FC/CYA Levels
& see if it goes away since you have purged recently. You may need to do this more than once. Use poolmath effects of adding to see dichlor’s effects on the ph to prevent lowering it too much. If subsequent slam fc rounds are needed you may need to use liquid chlorine instead.

Since my CYA is low, SLAM FC is pretty low (chart only allows for 20 CYA min, so I've gotta work with that for now) . I'll figure out how much dichlor to add, and hopefully get CYA up to the preferred levels in the process.

With CC that high, unless it's a false reading from "additives", if you didn't have a problem you do now.

Muriatic acid works better than dry acid btw. Have you read the sticky?

You gave me the impression the tub gets very little usage, is this last post contradictory? Usage REQUIRES enough sanitation to overcome waste products. In theory, with zero CC, silver ion, ozone, and UV would keep it that way with almost zero residual CHL.

Have you read the sticky?

It's good you got the test kit. Since it's purged, hopefully all you need do is take care of that CC situation and get ph in a good range. Have you read the sticky?

The only additive I've added is the Leisure Time Replenish dichlor. Upon a little googling the other 85% of its volume includes MPS, which interferes with chlorine tests
"Potassium monopersulfate (MPS or potassium peroxymonosulfate) is a non-chlorine oxidizer that will interfere in the total chlorine DPD test. Treating recreational water with MPS to remove bather waste can result in false high combined chlorine or total chlorine readings."
more info:

"Shocking" Interference

I may have to find some new reagent to add to neutralize the MPS reading. Great. I find some discussion here, but don't have more time tonight:

Proper procedures and chem test for MPS non-chlorine with ozonator, UV, Nature2

My jacuzzi was originally UV and Nature2 and had no ozone. I had the ozone installed last week to reduce the amount of chlorine exposure. After reading so much about the dichlor then chlorine method I got pretty familiar with keeping sanitization levels sustained. Checking with the Taylor kit, I...

www.troublefreepool.com

I have reread the sticky for chlorine in a spa again. If the CC is a result of MPS, then maybe all I'm really in need of is getting the pH down. It would be odd to have a bunch of gunk growing already after running Ahhsome several times and draining the tub.

 

[Mdragger88]

Hopefully its the sneaky mps reading as cc’s.
stick with 99% dichlor or liquid chlorine & poolmath should be quite accurate.
If you’ve been using the replenish it’s probably why your cya hasn’t increased as much as it’s only 15% dichlor, hasn’t been yielding much fc either probably.
Are you running the jets? That increases ph. You only need to run them about 5 minutes to circulate additions.
Keep adding enough acid to reach 7.6 then retest & repeat if necessary until you’re in the 7’s.

Slam level for 20 cya or below is 10ppm.
Minimum fc level for 20cya or below is 2ppm.

 

[aguywithaspa]

Hopefully its the sneaky mps reading as cc’s.
stick with 99% dichlor or liquid chlorine & poolmath should be quite accurate.
If you’ve been using the replenish it’s probably why your cya hasn’t increased as much as it’s only 15% dichlor, hasn’t been yielding much fc either probably.
Are you running the jets? That increases ph. You only need to run them about 5 minutes to circulate additions.
Keep adding enough acid to reach 7.6 then retest & repeat if necessary until you’re in the 7’s.

Slam level for 20 cya or below is 10ppm.
Minimum fc level for 20cya or below is 2ppm.

If I may not actually have CC levels too high, should I hold off on Slam? Or should I anyway since I've never done it and it probably can't hurt?
Thanks everyone again for the help.

 

[Mdragger88]

If I may not actually have CC levels too high, should I hold off on Slam? Or should I anyway since I've never done it and it probably can't hurt?
Thanks everyone again for the help.

I would raise to slam to play it safe, especially if you’ve been below minimum of 2ppm at anytime since your purge. It likely won’t stay at 10ppm for long

 

[Methuselah]

If you decide to slam with 99% dichlor use Poolmath to see how much to use but since you are already also trying to add CYA see how that gets raised ... maybe just target the cya level instead? It would push fc up high, but one time ain't gonna break anything.

Also know uv and ozone kill chl, so it may look like demand is higher than it actually is.

You didn't quite answer on bather load, so ok, you seem amicable to dichlor/bleach - have you looked at salt water generator alternatives?

With your system I suspect all you really needed is a CYA level 20-30 and liquid chlorinator if you went 6 years without anyone having health issues or smelling chlorimines.

 

[aguywithaspa]

I added another 3 teaspoons of dry acid (it's all I have right now). It's *still* 8.2+. At this point, I don't know how much I've added exactly, but probably like 8 teaspoons or more.
PoolMath shows that 3 tsp should've been enough to reduce from 8.2 to 7.6 in a 300 gal tub, much less 8. I don't know exactly how much higher than 8.2 it is, but it seems like that would be excessive. But I'm a stupid noob.

My junky old test strips now show that the range is pretty normal, if anything maybe low... though it's hard to exactly match the colors.
Is it possible I'm doing something wrong? you just fill to the top mark on the red comparator block and then add 5 drops of red, right?

 

[Newdude]

Is it possible I'm doing something wrong? you just fill to the top mark on the red comparator block and then add 5 drops of red, right?

That's it. And if it's particularly above 8.2/8.0 it may take several rounds of test/add/repeat. I had the exact same issue but reverse. We inherited a sky high 360-ish CYA and a PH off the charts low. It seemed like it needed 10 tries adding and mixing to get in in range, but it was probably only 6. Lol.

 

[aguywithaspa]

That's it. And if it's particularly above 8.2/8.0 it may take several rounds of test/add/repeat. I had the exact same issue but reverse. We inherited a sky high 360-ish CYA and a PH off the charts low. It seemed like it needed 10 tries adding and mixing to get in in range, but it was probably only 6. Lol.

It also occurs to me that I've had this container for the entire life of the spa, so it may be much less effective than normal, or not at all by now. Not sure how much it really degrades over time.

 

[RDspaguy]

Another issue that pool math cannot account for is aeration. You are running your jets when you add chemicals, which is mixing in alot of air if your air controls are open, which is all the time on a D1. It could be a factor, though I'm not sure how much of one.

 

[Newdude]

Not sure how much it really degrades over time.

Any of the acids keep their potency.

 

[Methuselah]

Breakdown of Bleach Over Time

If mixing in chemicals, running pump a few minutes with aeration should not matter.

 

[Mdragger88]

I added another 3 teaspoons of dry acid (it's all I have right now). It's *still* 8.2+. At this point, I don't know how much I've added exactly, but probably like 8 teaspoons or more.
PoolMath shows that 3 tsp should've been enough to reduce from 8.2 to 7.6 in a 300 gal tub, much less 8. I don't know exactly how much higher than 8.2 it is, but it seems like that would be excessive. But I'm a stupid noob.

My junky old test strips now show that the range is pretty normal, if anything maybe low... though it's hard to exactly match the colors.
Is it possible I'm doing something wrong? you just fill to the top mark on the red comparator block and then add 5 drops of red, right?

Since you’re out now- buy muriatic acid instead & just keep repeating the same process till you’re in the 7’s.
Like after 30 minutes- if you wait longer to retest the ph will have risen again. With your ta so high the ph will rise quickly.
Most here find around 50 or 60 helps moderate the ph rise. The lower ta gets the slower ph will rise. Check your ta every few rounds, if it has lowered the acid is working, you’re just not checking it before it rises again.

 

[aguywithaspa]

So it's been raining and busy with work, just got back to the tub yesterday.
I finally got down to the 7.6-7.7 range. Can't tell exactly, but it's between the 7.8 and 7.5 darkness of red.
I'm not sure I understand the jets increasing pH. Does it go up temporarily after they run, but then die back down? I mean it must or pH would just always be going up up up? Should I be good now, or get it a bit lower if pH will increase again?
TA before the last 2 tsp of acid added was 90.
I had about .5 FC so I added some more Replenish. Haven't had a chance to figure out what I might need exactly to neutralize MPS to accurately measure CC.

 

[PoolStored]

So it's been raining and busy with work, just got back to the tub yesterday.
I finally got down to the 7.6-7.7 range. Can't tell exactly, but it's between the 7.8 and 7.5 darkness of red.
I'm not sure I understand the jets increasing pH. Does it go up temporarily after they run, but then die back down? I mean it must or pH would just always be going up up up? Should I be good now, or get it a bit lower if pH will increase again?
TA before the last 2 tsp of acid added was 90.

Aeration causes the outgassing of CO2, which causes the pH to rise. It will not affect your TA. Unless something is done to lower pH, it will not "die back down."
When you add acid, it will lower the TA and lower pH.
At some point, when TA gets somewhere between 50-80, you will find your pH rise will slow and stabilize...likely around 7.8-8.0, and pH rise will slow or stabilize.

Deep End Reading:

PH TA Relationship - Further Reading

www.troublefreepool.com

 

[Mdragger88]

Haven't had a chance to figure out what I might need exactly to neutralize MPS to accurately measure CC.

MPS

A non chlorine oxidizer or ‘shock’. It is acidic and will cause lower pH and … Read more…

www.troublefreepool.com

This article lists the reagents needed

Water Testing Errors - Further Reading

It is much cheaper to ditch the Replenish & just get some 99% dichlor - it’s about $20 for 2# @ Wally World, amazon, etc.

 

[aguywithaspa]

MPS

A non chlorine oxidizer or ‘shock’. It is acidic and will cause lower pH and … Read more…

www.troublefreepool.com

This article lists the reagents needed

Water Testing Errors - Further Reading

It is much cheaper to ditch the Replenish & just get some 99% dichlor - it’s about $20 for 2# @ Wally World, amazon, etc.

Yes, thanks. I do already have some pure dichlor. But from that previous thread I linked (Proper procedures and chem test for MPS non-chlorine with ozonator, UV, Nature2) it is mentioned that MPS/Silver ions together work to sanitize, and is made less effective with high amounts of chlorine.

"No. Let me break it down this way - there are three (3) EPA-approved sanitation methods*** for hot tubs -

1. Chlorine
2. Bromine
3. MPS/silver

(*** I think Baquacil makes a spa product based on the biguanide/peroxide sanitation system, but I don't know of anyone that uses that much.)

The last one, MPS/Silver, is what Zodiac calls their "Nature2" system. Silver ions, when in the presence of a strong oxidizer like MPS or chlorine, can kill pathogens and stop disease transmission. However, hot tubs that run the silver ion system should be operated and kept at or above 96F at all times since that is what gives the correct kill times. Chlorine will react with silver and form silver chloride which is an insoluble salt in spa water that is near neutral pH (7-8 range). So, in order to make the system perform better, Zodiac switches MPS for the role of chlorine as the oxidizer. Remember that you need two things to create a sanitary body of water - you need a sanitizer to kill pathogens and an oxidizer to destroy bather waste. In the Nature2 System, the silver ions act as the sanitizer and the MPS acts as the oxidizer.

So you can use dichlor (or any form of chlorine) to "shock" the tub when the CCs get too high because the MPS can't handle it all (MPS is not as good as chlorine as an oxidizer). The downside to using chlorine is that it is going to take some of the silver out of the water which means the cartridge that the silver ions comes from (likely a mixture of silver nitrate and some other slowly dissolving additives) is going to get used up faster. This is also why the EPA does not allow silver to be used with chlorine in that system because the chlorine would make the concentration of silver ions too low to be effective."

So, if I were to use pure dichlor and no MPS wouldn't I be making the silver ion portion of the tub less effective? Unless I were to change to a pure chlorine type of sanitizing, which, if you're supposed to test every day, I honestly would rather not do? The silver/UV/ozone combo seems pretty good at maintaining clean levels once they're achieved.

 

[Mdragger88]

The silver ions should be a backup plan in my opinion & not the primary sanitizer. The kill rates aren’t great when compared to chlorine anyway.
The tfp recommendation is to always follow the
FC/CYA Levels & keep the tub’s fc above minimum for your cya at all times whether you use a mineral stick or not.
You will have to decide if you want to continue to use the system you have as your primary sanitizer (which you just have to trust is working based on how things look) or use chlorine as your primary sanitizer (where you can test all parameters & confirm them) & let the metal stick hang around for just in case.
If maintaining adequate standby chlorination is your concern then a salt water chlorine generator is a good choice. I have one (a saltron mini) & wouldn’t want to be without it.

 

[aguywithaspa]

So I've been continuing to try to maintain with my normal methods to see what I can learn.

PH has been becoming more stable, but now it's right at the upper limit of 7.8, and my TA is 40-50, so I don't know how to get it any lower without dropping TA below recommended levels. I see that you can maybe add baking soda to increase TA. But wouldn't that just allow PH to continue to rise faster again?

When using the Replenish to maintain sanitation, if I go a full week without using it, FC and CC are both barely noticeable color changes near 0-0.5 (and some of that CC may be MPS). Maintaining a 1-3 FC would require probably 2x a week capfuls of Replenish instead of once. Dimension one recommends once a week, but also to maintain 1-3 FC, which doesn't seem possible, at least without using more than they recommend at the 1x week timing. But that may be OK with the silver/UV keeping it clean.

CYA is still negligible even after ongoing maintenance with the Replenish dichlor/MPS. Not sure if some part of this system keeps the CYA lower than would normally be expected, but it is not building up at all. I can fill the whole tube without losing the black dot.

 

[Mdragger88]

So I've been continuing to try to maintain with my normal methods to see what I can learn.

PH has been becoming more stable, but now it's right at the upper limit of 7.8, and my TA is 40-50, so I don't know how to get it any lower without dropping TA below recommended levels. I see that you can maybe add baking soda to increase TA. But wouldn't that just allow PH to continue to rise faster again?

When using the Replenish to maintain sanitation, if I go a full week without using it, FC and CC are both barely noticeable color changes near 0-0.5 (and some of that CC may be MPS). Maintaining a 1-3 FC would require probably 2x a week capfuls of Replenish instead of once. Dimension one recommends once a week, but also to maintain 1-3 FC, which doesn't seem possible, at least without using more than they recommend at the 1x week timing. But that may be OK with the silver/UV keeping it clean.

CYA is still negligible even after ongoing maintenance with the Replenish dichlor/MPS. Not sure if some part of this system keeps the CYA lower than would normally be expected, but it is not building up at all. I can fill the whole tube without losing the black dot.

Since its a combo product it has a reduced amount of dichlor in it & adds less cya than what is listed in poolmath per dose. Not sure how much a capful is but only dosing the tub a couple times a week sounds like a recipe for disaster. The heat in a spa depletes cya some (the hotter the tub the faster this occurs) so combined with your minimal dosing of a reduced potency dichlor your unreadable cya <20ppm makes sense. If you’re not maintaining any residual fc & basically depending solely upon the silver you’re asking for trouble. Good luck to you with your “method”.
MRSA isn’t fun to live through.

 

[Methuselah]

Wow, just reread all 59 posts spanning over a year.

Here's a recap.

You don't use it much, your system is silver ion, UV, MPS, and (likely) ozone. You probably have a circulation pump although the short 30 minute filter cycles twice daily you mentioned suggest incongruity with that (I'm no expert!), use a factory mix for sanitation containing maybe 7% CYA, and typically dump once a year.

This led to brown flakes (now resolved by purging and cleaning behind jets), and now a short battle with ph.

You acquired a test kit but aren't seeing CYA, and still refer to test strips.

[\recap]

My first thought is this system works, and the UV failure may have caused a cascade of events. This is plausible to me because you may have had a biofilm issue before your first fill, and your "system" just kept it at bay until your UV failed (perhaps coupled with momentary low sanitation + recent bather load - all 100% conjecture).

That said, here's your problem. You can't test silver ion, UV, or Ozone, nor reliably test MPS. Worse is your reluctance to dispose of those test strips.

How big a problem is that? In your case maybe inconsequential. Maybe.

I'm going to suggest again, use mercuric acid for ph adjustment. Other than that you seem to have made it work.

One tip, if you know how much sanitizing granules you put in there, and CYA is about 7% of that, do the math and you know your CYA level. Your kit cant easily distinguish the low numbers you reported...

Best of luck!