Stain removal and water temperature

gavin123

Member
Aug 22, 2018
13
Sebastopol, CA
I am going to do an ascorbic acid stain removal treatment. I have iron stains - I did a vitamin C pill test.

I have all the chemicals recommended by Pool school - but I was wondering if there any recommendations on minimum water temperature. My current water temperature is in the 50F to 60F range.

Thanks

Gavin
 

gavin123

Member
Aug 22, 2018
13
Sebastopol, CA
If you used any pool store products that contain copper (i.e. Blue-this, or Blue-that), or algaecides from the pool store, copper is a real possibility.
I have never used it - but I have only had the house for a year. Here's a picture. You can see black circles where Vit-C tablet was and then the noticeably clearer spots around it when compared to rest of pool
 

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Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Kind of looks like copper spots, and the lighter mass area may be from removing algae stains or something. This is an older thread, so if you already have another thread started for your pool, let's stick with that one so we don't get confused. I can combine the comments so it all stays together.
 

gavin123

Member
Aug 22, 2018
13
Sebastopol, CA
Gavin, in your recent posts I don't see any test results, so at your next opportunity it would be good to see a full list of tests. It might also help us to see what's happening.
FC 1 (keeping low ready for potential Ascorbic treatment)
TA 80
Ph 7.4
CH 300
CYA 40

Is there a way to test for Copper? Also I read some older posts with similar symptoms saying the black stain went away a few days later.
 

Texas Splash

Mod Squad
TFP Expert
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Is there a way to test for Copper?
Copper test kits are generally more expensive. So even though we avoid pool store testing, that is one you could just look at if you have them run a random sample of tests for free. Just ignore all the other chatter since you do your own testing. So aside from your "pre-AA" low FC, the other numbers look quite good.

As for black stains that go away, back algae perhaps with a higher FC level and good amounts of physical brushing. Copper probably won't unless you apply some dry acid to the area. Dry acid (in a sock method) can help reduce some copper spots. If you have some you could try that.
 

gavin123

Member
Aug 22, 2018
13
Sebastopol, CA
Copper test kits are generally more expensive. So even though we avoid pool store testing, that is one you could just look at if you have them run a random sample of tests for free. Just ignore all the other chatter since you do your own testing. So aside from your "pre-AA" low FC, the other numbers look quite good.

As for black stains that go away, back algae perhaps with a higher FC level and good amounts of physical brushing. Copper probably won't unless you apply some dry acid to the area. Dry acid (in a sock method) can help reduce some copper spots. If you have some you could try that.
Dry Acid did not seem to do much to the pool stains. I tied in a sock and directly on plaster.The black stains (where I had left the Vit-C tablets) are considerably less black now after 24 hours. I tried a very small AA test on one of the steps to eliminate non-active ingredients in Vit-C tablet causing the blackening - but this showed a lot of black staining. I've attached a picture. I could remove this stain by using dry acid and wire brush - it was completely removed when I poured bleach into the water over the step (remember this is a chemical AA stain - not organic).

So where does this leave me? My current hypothesis is that I have both iron and copper staining. The Vitamin C lifted the iron stain around the area - but where the tablet came into contact with the plaster it reacted to some copper. So I am going to get the water tested for Iron and Copper at the pool store for free. Do you think it's worth trying Jack's Magic stain id kit to see further diagnose stain.
 

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Texas Splash

Mod Squad
TFP Expert
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So I am going to get the water tested for Iron and Copper at the pool store for free.
I think that's a very reasonable place to start. Post back with your results. Based on any potential iron/copper content, we'll have a much better idea of how to proceed. The fact you've been keeping the FC low in preperation for the AA is also good for the testing as well.
 

gavin123

Member
Aug 22, 2018
13
Sebastopol, CA
I think that's a very reasonable place to start. Post back with your results. Based on any potential iron/copper content, we'll have a much better idea of how to proceed. The fact you've been keeping the FC low in preperation for the AA is also good for the testing as well.
So the pool store said there is no iron or copper in the water. They also said I have zero CYA! I am testing at 40 CYA. It was close to 90 in the fall - but winter rain has replaced probably about 40% of water. Incidentally,the same store said I had zero CYA in the fall too. I stopped using chlorine pucks in favor of TFPC in the fall and have been very happy with water balance.

I have ordered a Jack’s Magic stain Id kit. Hopefully that will help narrow down stains. If I do have both iron and copper stains - then would Citric Acid be the way to go? I have read that Citric can eliminate copper stains as well as Iron. What do you think?
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Not completely surprised that the pool store showed no metals, but it's good you tried. Ordering the Magic Jack's test kit is a good choice at this point. Citric acid (i.e. Vitamin C) will remove acid, but probably not copper. There's a chance it could aggrivate the copper stains .... "if" that's what those others are. You can try the AA treatment first to address the iron since you're already prepped for that, then try something like the "Blue Stuff" for any potential copper staining.

But the general rule of thumb is:
- Organic stanins: removed/lightened by chlorine (i.e. tablet/puck test)
- Iron: Vitamin C tab test/AA treatment
- Copper: aggrevated by Vitamin C test, removed/lightened by dry acid test in a sock; often times best removed by drain & acid wash. Magic Jack's Blue Stuff may help.
 

mattchase00

In The Industry
Feb 27, 2019
27
Largo, FL
Not completely surprised that the pool store showed no metals, but it's good you tried. Ordering the Magic Jack's test kit is a good choice at this point. Citric acid (i.e. Vitamin C) will remove acid, but probably not copper. There's a chance it could aggrivate the copper stains .... "if" that's what those others are. You can try the AA treatment first to address the iron since you're already prepped for that, then try something like the "Blue Stuff" for any potential copper staining.

But the general rule of thumb is:
- Organic stanins: removed/lightened by chlorine (i.e. tablet/puck test)
- Iron: Vitamin C tab test/AA treatment
- Copper: aggrevated by Vitamin C test, removed/lightened by dry acid test in a sock; often times best removed by drain & acid wash. Magic Jack's Blue Stuff may help.

If you haven't ordered Jack's Stain ID kit yet? Give me a call and I'll send you one for free..

Matt
Technical Support
Jack's Magic Products
 
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gavin123

Member
Aug 22, 2018
13
Sebastopol, CA
Thanks for the offer. Unfortunately I just ordered it. I'll post the results.
OK tested with Jack's Stain ID kit. Looks like it's Iron. Copper packet did not do anything. I'll move onto treatment in a week or so. I just need the water temps over 65-70. It's a bit cold this weekend. Jack's Iron test also went black after initially removing stain (like my vitamin C test). I suspect it will clear just like Vitamin C black stains did in 24-36 hours or so. Not sure of chemistry going on here - but it doesn't seem to be related to copper in any way as stain is temporary.
 

mattchase00

In The Industry
Feb 27, 2019
27
Largo, FL
Usually if Jack's Iron product turns stain black indicates the presence of copper or oxidized copper.. are you sure H20 chemistry was exactly within parameters on stain ID box? Jack's #2 is somewhat compromised in Ph above 7.4 CL2 above 3ppm and water temps below 65 degrees. Calcium above 400ppm and CYA above 70ppm and TDS above 1200ppm

Matt
 

gavin123

Member
Aug 22, 2018
13
Sebastopol, CA
Usually if Jack's Iron product turns stain black indicates the presence of copper or oxidized copper.. are you sure H20 chemistry was exactly within parameters on stain ID box? Jack's #2 is somewhat compromised in Ph above 7.4 CL2 above 3ppm and water temps below 65 degrees. Calcium above 400ppm and CYA above 70ppm and TDS above 1200ppm

Matt
Iron test removed stain and then went black a few minutes later. 36 hours later the black area is completely cleared up. The Copper test showed no improvement - so I don't think it can be Copper.

Ph was 7.2. FC was 0.5ppm. Water temp about 66F. CYA 40ppm. I haven't tested Calcium or TDS recently - but last test CH was around 300.
 

gavin123

Member
Aug 22, 2018
13
Sebastopol, CA
So I did the treatment. I added Polyquat the day before starting treatment. Water temp was 71F. FC was 0, Ph at 7.2, and TA at 80. I added 3lb of AA. It lifted a lot of the stains - but not all. I added a further 2 lbs after a run to the store. About 3 hours after adding initial dose of AA - I then added 2 bottles of Metal Free - more than I needed - that is a total of 68 oz. I went to bed happy - thinking pool would look even better in the morning. In the morning I noticed the stains started to re-appear. After 24 hours I started to re balance water. Ph had dropped to 7.0 and TA was a 60. I added Washing Soda. Ph went to 7.2 and TA was at 65. I added baking soda to bring TA back up to 70. I then started adding chlorine. After 72 hours the FC is starting to stabilize - after probably adding 8-9 gallons over the last 3 days.

The stains are only slightly better than went I started - but obviously something went wrong as the stains started to appear quickly. Maybe I didn't add sequestrant quicker enough - I waited 3 hours after starting AA - mainly because I had to run to store to get more AA.

Overall this didn't work. Maybe I'll try next year by adding more AA and adding sequestrant a few minutes after starting treatment.

Any thoughts?