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Look like it's probably iron.

Have you had any dust storms recently?

Sometimes the dust contains iron.

I think that you might have some copper staining as well.

The iron would probably respond to an ascorbic acid treatment. Copper would probably not be easy to treat.

Try the tests as described to see what that shows.
 
Good morning, Yann.
Of the two, if the readings are correct, copper is higher and ergo possibly the culprit, though as James said, readings are tricky. See which of those tests work best before considering any of the treatments I mention below.

I've had posters report good results using this tool that i will link you too if the staining is broad on plaster, but go carefully if you do this treatment as all kinds of acid washing wear plaster.
You use MA and feed it to this wand: https://www.amazon.com/dp/B00C7UGLFY/ref=asc_df_B00C7UGLFY5289795/?tag=hyprod-20&creative=394997&creativeASIN=B00C7UGLFY&linkCode=df0&hvadid=198092708878&hvpos=1o1&hvnetw=g&hvrand=13617769088985800379&hvpone=&hvptwo=&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=1019111&hvtargid=pla-348166170622

There is also a copper stain treatment available from Jacks Magic using sulfamic acid, i believe, but the caveat is that it will mess with your cc readings and fight your FC for a good long while after treatment.

Iron is easier to nail with Ascorbic Acid treatment, but the treatment itself is a bit tricky to come out of as it also fights FC.

So report back which test works better.

In the mean time, even though your metal levels are quite low, there are two things when you have metals that help: #1 is to keep ph lower than normal. Eg 7.2-7.4. The second is to actually avoid slamming, which can precipitate metals. So just keeping normal TFP FC/cya levels, not elevated levels going forward ;)
 
Thank you very much everyone for all your advice.

I will try your recommended tests asap.

I mentioned earlier 2 different spa ph down powders. Which one is best please?

yann said:
ive got 2 options for spa ph down. Which one is Best ?
920g/kg hydroxytricarballylic acid or
1000g/kg sodium bisulphate

thanks
Click to expand...

Thanks again
 
JamesW said:
Look like it's probably iron.

Have you had any dust storms recently?

Sometimes the dust contains iron.
Click to expand...

James, we do not get dust storms here, but the stains appeared after quite a few days of heavy storm, with lots of wind causing lots of debris and regular soil (dust) to land in the pool
 
Glad you have the real experts helping you out mate :)

I noticed that copper reading you got, and immediately thought it might be worthwhile (when you get a chance, not urgent) to get the metals checked at a couple more pool stores and see if the number marries up. But that said, the tests mentioned by JamesW and Swampwoman are the most important things to do.
 
Swampwoman said:
Hi Yan. Sorry you're not getting results but I have a hunch, as does James I think ;)

Re:

Pucks are acidic and acid will sometimes liberate a metal stain. So the following min-tests might help demystify the stains.

1. If you have or can get a small bit of dry acid (eg little bottle of spa ph down), put the powder in a sock, put on a rubber glove to protect your hand, rub the spots a bit and see if they don't lighten. Could be copper, whch can blacken, or maganese, or some combo of metallic plus scale.

2. Crush up some vitamin c in a sock and also rub/apply. If the spot initially darkens, but later starts to lighten a bit, or just blackens, the culprit likely involves copper. Don't use Ascorbic acid to clean in this case; but you could use an acid-feeding wand to carefully clean the area with muriatic acid.

If, on the other hand, vitamin c completely lifts the area, its more likely maganese or discolored iron and should respond to either an AA treatment or spot treating with ascorbic acid loaded into a dishwasher wand with cap, mix AA with water 50/50.

Let us know if either of the experiments gve you anymore info to work with. If so, I can post a link to the type of underwater wand that works with MA.
Click to expand...

Hi all

I have finally had time to proceed with the tests.
I would not say any was quite obviously conclusive.
However the Spa pH down down seemed to have an effect on the stains. No blackening, just fading.
Vit C test had no effect, or at least no visible effect on the stains.
 
I think that it's probably iron or other metal. I would probably ignore it if it's not bothering you. Add a maintenance of sequestrant on a regular basis, maintain good chemistry and brush frequently.
 
Ok

As long as it's not organic and the pool is safe for swimming, then it's only cosmetic.

I'd like to have it fixed anyway because it doesn't look good.

Any particular sequestrant I should look for?

Also, my pool is usually happy at pH 7.6-7.8 with MA additions only once a month or so (TA80)
Should I aim for pH 7.2-7.4 as a rule like SwampWoman suggested, even if it means more regular additions of MA and probably a significant drop in TA as a consequence?

Again, I would like to thank you all for your help and support trying to fix this issue.
Much appreciated.

Cheers

Some time this week I will follow Jet's advice and have the water tested in the 3 local pool shops.
They all use the same testing system, so we'll see if they're consistent with their results... :evil:
 

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I have no experience with metal sequestrants, but here's two example products that Swampwoman or JamesW could maybe shed some light on from the MSDS:

Metal Remover Stain Removel for pools- Direct Pool Supplies
https://www.swimmingpoolspares.com.au/msds/Metal-Solution-03-15.pdf

IQ Pool Solutions Metal Magnet | Interquad
http://www.interquad.com.au/uploaded/pdf/14-iq-pool-solutions-metal-magnetpdf

IQ also has a stain remover: http://www.interquad.com.au/uploaded/pdf/13-iq-pool-solutions-stain-removerpdf

If the additional testing of copper continues to indicate 0.7 ppm, you may want to consider replacing the water, rather than needing sequestrants indefinitely, but I'll leave it to the experts to consider that. The copper is most likely there from past use of cheap algaecides.

I think you're on Sydney water, but if not, you could also get your fill water tested. If fill water is Sydney water, or otherwise good, then draining and refilling is an option to get rid of metals. My pool cost $80 to fill, so that might be competitive. You still sequester the metals once before draining, to help get them out. Draining a pool is a big deal with significant risks to think about, so if you go down that path, be sure to discuss it here first, or hire someone with liability insurance to do it.
 
needsajet said:
I have no experience with metal sequestrants, but here's an example product that Swampwoman or JamesW could maybe shed some light on from the MSDS:

Metal Remover Stain Removel for pools- Direct Pool Supplies
https://www.swimmingpoolspares.com.au/msds/Metal-Solution-03-15.pdf

IQ Pool Solutions Metal Magnet | Interquad
http://www.interquad.com.au/uploaded/pdf/14-iq-pool-solutions-metal-magnetpdf

IQ also has a stain remover: http://www.interquad.com.au/uploaded/pdf/13-iq-pool-solutions-stain-removerpdf

If the additional testing of copper continues to indicate 0.7 ppm, you may want to consider replacing the water, rather than needing sequestrants indefinitely, but I'll leave it to the experts to consider that. The copper is most likely there from past use of cheap algaecides.

I think you're on Sydney water, but if not, you could also get your fill water tested. If fill water is Sydney water, or otherwise good, then draining and refilling is an option to get rid of metals. My pool cost $80 to fill, so that might be competitive. You still sequester the metals once before draining, to help get them out. Draining a pool is a big deal with significant risks to think about, so if you go down that path, be sure to discuss it here first, or hire someone with liability insurance to do it.
Click to expand...

Thanks Jet

I'll wait to hear what the experts have to say, as I don't really want to empty the pool, too scared of the risks.
Also, I am not sure how to do that.
Even though I've got a main drain at the deep end, it doesn't seem to be working when the pump is on, and I can't find a valve near the pump to switch from skimmer box to main drain.
It seems that the pump is only getting its supply from the skimmer box.
 
It's common for the main drain to be disabled. Sometimes it's because of clay shifting/drying/swelling causing a crack in the underground plumbing. Some people just disable it to eliminate the risk of having a main drain. I bought a $60 submersible pump for mine, and can also use the vacuum hose for part way down, or there's some other methods.

Yeh, I'm looking forward to hearing back as well, learning right along with yas!
 
I guess I could use the vacuum hose.

I was just looking at my pool stores results before I went TFP.
Metal readings were always at 0.1ppm for both iron and copper.

I wonder what made the copper go up to 0.7ppm, since I never used algaecide and I'm on Sydney Water just like you.
Could be testing error of course, we all know stores aren't reliable.
 
Hi Yann. Regarding this:
However the Spa pH down down seemed to have an effect on the stains. No blackening, just fading.
Click to expand...

Sometimes a metal will combine with scale, in which case acid works better at cleaning it. This can happen with either copper or iron.

In your shoes, I'd take a 2-step approach. First, I'd add sequestrant just to see if by itself it improved the stains.

I don't know if my favorites, Metal Magic or Jacks Magic, are available in AU. They are HEDP -- phosphonic acid.

You'd want sequestrant in the water anyway before lifting the stain to prevent re-precipitation. With Metal Magic, you don't have to lower the ph below 7.6 to work, which makes it more convenient.

If adding it didn't make much difference on the stain, however, I might consider applying acid with that wand I linked to earlier. On one hand, this type of "underwater acid wash" does expedite the wear on plaster, but on the other, some people are really bothered by staining, so to them, its worth treatment. I just want you to be aware that you don't want to be doing an acid wash as a "go to" treatment all the time ;)

That's why determining the source of metals ultimately helps in control. The source isn't always in your raw source water...sometimes in-pool corrosion can leach metals.
If you have a heater and its older, copper can leach from the heat exchanger over time. If your household plumbing is copper, you can also have trace amounts over time.
Other sources of in-pool metals, eg iron, include erosion of hand rails (eg rust inside the rail communicates with water and leaches), screws, etc. This can happen a bit faster in salt water pools. It might also be good to check that your equipment is bonded correctly if the pool is new to you...eg can you see bond wires at your equipment pad?

Your levels are pretty low in the realm of metals, even at .7 ppm of copper, so I rather expect its legacy copper from a prior treatment of algaecide. Over time, you should be able to dilute it further, and likely manage it in terms of staining merely by sequestrant and avoiding further slams by keeping the TFP FC/cya ratio (which will mean you never need to slam again ;)

Hope that helps but keep us posted.
Cheers.
 
Yann, that product is specifically for calcium build up and is a poly acrylite product, which is different from HEDP and in my opinion, reportedly less effective for sequestering metals (which it doesn't even claim to do.)

However, since the previous owners had it on hand, that tells me that they had hard water trouble or a tendency to produce scale. It also makes me think that if you can get proteam's metal magic, it might be the best product for you as its fairly aggressive with calcium scale as well.

Can you post up your current readings? Where is your ch level riding? If you plug all your numbers into pool math, what does the "csi" box say? You have a salt water pool, so avoiding scale build up is relevant to keeping your salt cell clean.

With my swg, I keep my "csi" just slightly negative at -.3 to accomplish this. More on that later if your ch is high, but the leftover product tipped me off a bit to what you're predecessors were treating for.
 
Swampwoman said:
Yann, that product is specifically for calcium build up and is a poly acrylite product, which is different from HEDP and in my opinion, reportedly less effective for sequestering metals (which it doesn't even claim to do.)

However, since the previous owners had it on hand, that tells me that they had hard water trouble or a tendency to produce scale. It also makes me think that if you can get proteam's metal magic, it might be the best product for you as its fairly aggressive with calcium scale as well.

Can you post up your current readings? Where is your ch level riding? If you plug all your numbers into pool math, what does the "csi" box say? You have a salt water pool, so avoiding scale build up is relevant to keeping your salt cell clean.

With my swg, I keep my "csi" just slightly negative at -.3 to accomplish this. More on that later if your ch is high, but the leftover product tipped me off a bit to what you're predecessors were treating for.
Click to expand...

I would say the previous owner had scale issue. The cell was covered in large thick white deposits which I had to scrap off and acid wash the cell.
From my early shop results, I think calcium was fairly low because the shop made me add 4kg of CH up, then when I embraced TFP I had to add a bit more CH to reach CSI above -0.6.
So how is that possible to have scale issues with low CH and low CSI?
He could have been pool $hopped too, since it was his recommendations to me when I bought the house: "take a sample to the shop every 2-4 weeks and they'll tell you what to add"

Since adopting TFP and keeping my CSI between -0.6 and -0.3, I haven't had any signs of scale deposits on the cell plates.

That's my current readings:
Results from poollogger.com

FC: 9
CC: 0
PH: 7.2
TA: 100
CH: 375
CYA: 70
Temp: 25
Salt: 4200
CSI: -0.48

My fill water has a CH of 50-75ppm
Also, the water quality report seems to show 2mg/l of copper.... http://www.sydneywater.com.au/web/groups/publicwebcontent/documents/document/zgrf/mdq0/~edisp/dd_044726.pdf
 

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