Pool Stain Identification Help

[cth6]

All,

I am hoping that you all can help. I reciently found this site and have spent some time reviewing post. They have been very helpful, but I am still having challenges.

First a bit about my pool…
4 year old 14,000 gallon pool with spa in Central FL. Finish is a blue quartz diamond brite. The pool is heated with solar and a Hayward Propane heater. Salt system for sanitation. Pool is usally 92F for 8 months a year. Pool turns 3 times a day during the summer and 2 during the winter. Tested weekly and very rare if outside of any of the values.

This is the 5th pool that I build as a General Contractor. I watched every step but the plaster finish. They showed up a day early and did it while I was at my real job. I have had some issues with the finish quality. Not bad, just not up to the par of the rest of the pool.

About the stain….
About 24 months ago I started to notice the deep end showing some darker areas (light tan). It looked like someone put a sand colored diamond brite into the hopper and accidently mixed it in. I blew it off as a bad install.

Over the course of the next 12 months it started to work its way on all of the bottom surfaces of the pool. It is a light tan / gray color. I dove the pool and tried pumice to scrub it off (no avail). I went to my local pool store to get a test kit (Jack’s). It took 3 weeks to get the right numbers on all of the conditions. Ran the test and nothing really hit. I called Jack’s and the tech asked a bunch of questions and recommended that I keep pH at 7.0-7.2, Alk at 80 or less and put 1 Qt of Magenta stuff in and every week following add 8 oz more for a total of 5 weeks. The stains did not lighten at all, but I did notice a very little bit blue green metal in the filter (guessing copper) as well as a bunch of sludge.

The tech recommended that I wait until until Spring to do another test because the water temp was getting too low for effective treatment.

So today, I tested using another kit. This was from Pinch a Penny (but by Jack’s) During the Iron/Cobalt test, I noticed a few light pink stains appear on the surface of the test stain (about 6 the size of rice grains). They are slowly fading, but no real change to the base stain.

The Stop Stain Test did nothing.

The O2 safe shock test (Oxidized Copper) ½ pouch of O2 safe shock for 2-3 minutes, followed by ½ packet of stop stains for a few seconds. I did notice a very light yellow ring around the pile of the O2 safe, I lightly brushed it with my hand to the next step in the spa so I could add the stop stains. The stop stains did not do anything. The stain looks about the same. Then when I stood up, I noticed that the 2nd step had dark yellow stains all over it. The dark yellow stains faded over 10 minutes with some minor brushing. Overall, I am having a hard time telling if the base stain is any lighter.

After reading the site, I did the Vitamin C test, and no change to the stain.

Here are the numbers for the pool as of Saturday. (Remember I was doing the Jack’s test so I had to get a few numbers pretty low)
Temp> 91
Saturation Idx> .3
TDS> 4100
CYA> 77
Total CL > .9
Free CL> .8
Ph> 7.2
Total Alk> 97
Adj Total Alk> 74
Tot Hardness> 244
Salt> 2900

Usually pool sits at
CYA> 100
Total and Free CL > 2
pH > 7.5
Total Alk > 100
Adj Alk >95

I am open to suggestions at this point. I am a bit leary about calling the tech back from Jack’s, because I felt like he was guessing. I offered to send pictures, but he said that with all of his experience he did not have to see the pool.

Thanks.

Chad

 

[reebok]

I offered to send pictures, but he said that with all of his experience he did not have to see the pool.

I am not a stain expert, though the ones here probably could do it without pictures but you know what they say about pictures being 1,000 words. I did a word count on your post and it was 712 words, so that means a picture is required
where in central fl are you? it looks like you usually keep your cya too high, and your fc too low, so I suppose they could be organic stains. I'm guessing you use algaecide also? which one?

 

[cth6]

The Spa has the light colored stains (much like the pool started) Image 407 [attachment=0:2fk7p1wr]IMG_0407.JPG[/attachment:2fk7p1wr]

The pool has been taking on a darker shade as time progressess. Image 405 [attachment=1:2fk7p1wr]IMG_0405.JPG[/attachment:2fk7p1wr]

 

[JasonLion]

Does the stained area feel rough compared to the rest of the pool surface? Also, how careful are you about keeping the PH in range? Has the PH been above 8.0?

 

[cth6]

I offered to send pictures, but he said that with all of his experience he did not have to see the pool.

I am not a stain expert, though the ones here probably could do it without pictures but you know what they say about pictures being 1,000 words. I did a word count on your post and it was 712 words, so that means a picture is required
where in central fl are you? it looks like you usually keep your cya too high, and your fc too low, so I suppose they could be organic stains. I'm guessing you use algaecide also? which one?

How about 2. :-D I was posting in a second email when your message came in. I had to shrink them down a bit to make them fit. I live in Winter Garden (just west of Orlando). About 3 or 4 times a year I dump in some BioGuard Optimizer Plus. Water clarity has been excellent since the begining. Only one mustard issue when the salt cell when south after 13 months of use, just so happened while I was on vacation.

I ruled out organics when they first appeared and again a few weeks ago. Used some Chlorine based shock and set it on the stain overnight. Next morning no change.

What are you recommending for the CYA and FC?

Thanks for the quick response.

 

[cth6]

Does the stained area feel rough compared to the rest of the pool surface? Also, how careful are you about keeping the PH in range? Has the PH been above 8.0?

In general the stain feels the same as the rest of the pool. That is why I first thought someone added a bag of the wrong color diamond brite when it was first in the deep end. There is very little scale in the pool. There is some minor under the spillway on the spa.

I am pretty anal with the chemicals in the pool. I can't say that I have seen it over 8.0, but that does not mean that it has never been there.

 

[reebok]

this is really off-topic as far as your stain issue goes, like I say I'm no stain guru. but your test results are a little strange, how are you obtaining them? strips? pool store? are you using an algaecide? your fc level is based on your cya. see the chart in pool-school/ by following those levels, you won't have to use algaecide or any extra junk. just chlorine and acid for most people (and in your case you don't even have to bother with chlorine, just salt occasionally). bioguard optimizer plus is a borate product. this forum highly recommends borates for many reasons, but you could do it cheaper if you wanted to by using 20 mule team borax which is found in the laundry aisle of walmart or other grocery stores. so-you-want-to-add-borates-to-your-pool-why-and-how-t4921.html

 

[cth6]

this is really off-topic as far as your stain issue goes, like I say I'm no stain guru. but your test results are a little strange, how are you obtaining them? strips? pool store? are you using an algaecide? your fc level is based on your cya. see the chart in pool-school/ by following those levels, you won't have to use algaecide or any extra junk. just chlorine and acid for most people (and in your case you don't even have to bother with chlorine, just salt occasionally). bioguard optimizer plus is a borate product. this forum highly recommends borates for many reasons, but you could do it cheaper if you wanted to by using 20 mule team borax which is found in the laundry aisle of walmart or other grocery stores. so-you-want-to-add-borates-to-your-pool-why-and-how-t4921.html

The results quoted are from my local pool store. They use test using strips and the BioGuard reader on the tester. I routely send additional water samples to another store (pinch a penny) to validate the test, as well as using a test kit at home using a Taylor K2005. I find that Pinch a Penny is usally the one that is off from the other two. My test kit can't test everything that the BioGuard, but I routinely validate the pH, Alk, CYA and hardness.

Thanks for the links, I looked through some the past few days. Gave me a bunch to consider.

 

[duraleigh]

I'm not so sure I'd rule out organics just yet. Frequently, organic stains can take weeks to be reduced or eliminated.

If it were my pool (and because I am cheap) I would elevate my FC to 10-15+ppm and keep it at that level for at least 10 days observing the stain each day. It certainly will cost very little money (just the extra Clorox to bring it up....I wouldn't use the SWG) and will absolutleyrule out organics which I don't think has quite been done.

If your FC has historically been at it's current level, that's too low to prevent organics from forming in your pool. (5-7ppm with a CYA of 100 is generally close to what we recommend.)

 

[cth6]

I'm not so sure I'd rule out organics just yet. Frequently, organic stains can take weeks to be reduced or eliminated.

If it were my pool (and because I am cheap) I would elevate my FC to 10-15+ppm and keep it at that level for at least 10 days observing the stain each day. It certainly will cost very little money (just the extra Clorox to bring it up....I wouldn't use the SWG) and will absolutleyrule out organics which I don't think has quite been done.

If your FC has historically been at it's current level, that's too low to prevent organics from forming in your pool. (5-7ppm with a CYA of 100 is generally close to what we recommend.)

The FC has been way over 15ppm for 9 days now. I isolated the spa and used the pump to circulate it 3 times per day before letting it run the main pool. I brought the FC off the charts. (1 drop per water test was showing almost 5ppm today, so somewhere around 25ppm) It's definately is not organic. But I must say, I don't think I have ever seen the drain covers so white.

Any recommendations on the best way to remove copper stains? or other tests to rule it out or confirm the stain?

 

[frustratedpoolmom]

Copper stains are removed via a drain/and acid wash, not really a DIY kind of thing.

 

[cth6]

Copper stains are removed via a drain/and acid wash, not really a DIY kind of thing.

Thanks. Not what I was hoping to hear, but may not have any other choice.

 

[mbar]

You can crush up some vitamin C tablets put them in a sock and rub it on the stain - if they lighten then they are mineral stains. You can also try some dry acid (ph down) in a sock - it will not fade the stains as quickly as vitamin C which is ascorbic acid. If the stains lighten then you can do the ascorbic acid treatment which is is the stickies - or you can use citric acid ( it is cheaper and it works, though not as fast).