Yet another stain problem, iron or copper?

[jumpinjackieflash]

I really appreciate anyone who can help me with this.

We had the pool resurfaced last year. White plaster with blue aggregate. All was great until about 2 mos. ago when we thought we had mustard algae. We don't service the pool ourselves b/c it's so large (close to 50,000 gals.) and has a DE filter. I told the pool service co. that we had what appeared to be algae and I think he may have added some algaecide at that point. The stains did not go away. We brushed the entire pool. Still, the staining remained.

I contacted the pool contractor we used and they came out when I was not home and supposedly looked at it, and said it's not hydration but that the chlorine was too high and to tell the service co. to back off on the chlorine. I did that, and then we went on holiday so I did not see the pool for 3 weeks. There are 2 clean spots in the spa and the pool contractor says they used Jack's Magic #2 to spot treat the stains.

But we still have staining, and the service co. seems unable to figure out what to do. I have done some research and it would appear to be either copper or iron. No one here has blonde hair or I'd test it on them! The dog is white, maybe I should see if she'd turn green?

I rubbed half of a cut lemon on the stain and it did get lighter/go away. I am planning to fire the pool service company b/c the guy has not figured out how to get rid of the stains.

Please tell me what to do and how to do it. So far, it seems to require a buttload of Jack's Magic #2 and the Purple Stuff, which is going to cost me a small fortune, but the pool is huge and it can't be spot treated. I am trying to upload a photo but Windows keeps jamming.

 

[jumpinjackieflash]

The shadows are just trees above the pool. It may not look bad but it's dirty-looking.

 

[Swampwoman]

Hi there.
I guess the course of action recommended might to a degree depend on your intent around managing the pool. By this, I mean that if you were just going to get another pool service, you might want to let them manage the staining, because by attrition, their methods are generally different than TFP (because they're not there daily to test.)

If you plan to take over the pool maintenance yourself, you would need to get a proper test kit and post your chemistry levels. Just about everything involved in stain management requires accurate testing...that's because treatments like AA require manipulating the chlorine and PH levels for it to work correctly. (If you haven't already, read the AA or ascorbic acid treatment thread in pool school and you'll see why.)

You also need, with metals, to keep your ph well controlled and lower than typical reccs, so 7.2 to maybe 7.4. You didn't mention if you had SWG, but if you do, you may find that your ph raises beyond that range a little faster and in either case, faster than a weekly visit from a pool tech can adequately control.

If you already have a TFT kit or Taylor2006, please post your results. People with more plaster experience could then help you determine whether or not your CSI is in range and whether or not calcium scale is part of the issue.

I have a vinyl liner, so my areas of assistance will be incomplete, except to share what's currently working for me, which applies more to iron than copper (my copper level is about .3 ppm...borderline for staining).

The fact that a lemon worked, however, suggests in part that iron could be in the mix.

This year I switched from jack's pink (good for iron) to Metal Magic (proteam) which I found to be slightly more cost effective (at Pool Geek .com, by the case, free shipping and about 17 bucks a bottle plus I use less). With your size of pool, this might be germane

Instead of doing the usual AA treatment for my overwinter iron staining, I did a sponge test and used 5 bottles of Metal magic. It lifted the stain and sequestered the metals very effectively, and I didn't have to drop the ph to use it. So it was a little more convenient for me. Then I proceeded to dose up more than they suggest -- eg adding 6 oz weekly instead of a monthly maintenance amount. For me, that meant a stain free summer. YMMV, but it may be worth a try. I should mention that this method doesn't reliably work for everyone, which is why TFP regularly recommends the AA treatment instead - more consistent results. Hope that gives you some options at any rate.

The only thing I find suspicious about your pictures is that your white plastic returns are not discolored. When I get staining, my returns and steps discolor as well. But mine are old, and yours are new. But it makes me think that your issue might involve scale and plaster-specific issues rather than a straight up "iron in the water" scenario.

 

[jumpinjackieflash]

Thanks so much for your response. The returns were more stained in the beginning. The stains have lightened somewhat, perhaps when the pool service dropped the chlorine level as the pool contractor suggested. It is difficult to say exactly what happened since we were away for 3 weeks.

I see your point about letting the next servicing company deal with the stains. I have thought of using it as a sort of test - call several companies and ask them to come out and evaluate the pool to see what they would recommend. I am rather a hands-on pool owner and especially since both parties (the service company and the contractor) have been remiss in dealing with the problem in a timely manner. I can understand the contractor refusing to get involved since it does seem to be a chemistry problem and not a plaster problem per se.

As for numbers, I took the water to a local supply store and I will list the results. (We have a traditional chlorine pool, not SWCG.)

FAC: 7 (high)
TAC: 7 (high)
CH: 240
CYA: 100 (high)
Alk: 80
pH: 7.8 (service co said 7.2, but I have only ever seen him use a dipstick, not a full kit)
CU 0
Iron 0
TDS: 800
Phosphates: 300 (high)

It is strange to me that this analysis showed no copper and no iron, especially since the stain certainly lightened when I rubbed the lemon on it. Are there other stains which respond to AA?

 

[duraleigh]

Of course, we encourage everyone to manage their own pool. We are a group of hands-on folks.

If you decide to do that, you will need to start by getting a test kit you can use and get meaningful results. I think, in the past, your pool chemistry has gotten away from the service companies and it's likely only a caring, willing-to-learn owner like yourself can get it back in line.

So I would suggest you make a decision whether or not to manage your own pool's chemistry (you could still get a service company to handle the more physical aspects of things if you like). If you make that choice, then I would focus strictly on learning ("The ABC's of Pool Water Chemistry" up in Pool School) how our methods work and getting your pool within a set of guidelines. (For example, your CYA is very much too high and will require a large adjustment to get it in line)

Now, after all that, it time to tackle the stains. You may be pleasantly surprised that in a properly balanced pool your stains will fade into insignificance. Even if they don't, you can begin the process of eliminating them forever but making an absolute positive identification of the type of stain you have and then applying the correct treatment for that stain. Most pool companies try a scattershot approach to stains and often are not very sure what gave them success, if any at all.

So, that's a VERY long-winded answer, but in a nutshell, take over your chemistry yourself, bring your pool into equilibrium and then from that known starting point tackling the stains can be pretty quick and easy withou guesswork.

 

[jumpinjackieflash]

I'm not thrilled about the CYA. It is expensive to drain and fill a pool - and we just did it last year. I wish there was some way to lower the CYA level without draining the pool. I sure don't want to have to do this every year. And to add bleach to such a huge pool...that's a daunting proposal.

I would say the staining might have come from the algaecide, but it was actually there before the algaecide was applied.

The main thing I don't want to do is to allow the stain to remain so long that it damages the new plaster.

 

[Swampwoman]

Hi again.
If your ph is really 7.8, you would do well to lower it to 7.2-7.4...even if you contract out part of the service, it would be worth your while to get a good test kit just to control the ph, which is exactly what will precipitate metals and cause staining.

But here is some food for thought about maintaining at least the chemistry yourself -- if you have to bother to know enough to troubleshoot the techs, I'm thinking for the five minutes it would cost you per day, you might as well save yourself the money and just use techs to do things you don't like (eg. In my case, put on the winter cover.)

Your CYA is that high (and you did a water change a year ago) BECAUSE your service pretty much has to use a stabilized product like Trichlor pucks BECAUSE they can only be there every so often. Your FC, in fact, is NOT that high considering that CYA at that level hampers its capacity to disinfect -- getting that ratio right is what tfp's all about

Maintaining the chemistry yourself wouldnt actually be much different than, for example, what i do. eg. size of the pool may make a diffrence in cleaning, but not balancing. Your pool is about twice the size of mine. That means instead of adding roughly half a gallon of 12% liquid chlorine a day in peak swim season, you'd add a gallon. Once the jug is in your hand, not sure there's that much of a difference (You could also automate with a pump, or consider swg.) By using liquid chlorine or swg, you avoid the otherwise inevitable build up of cya. The techs just can't pull that off bless you have them come ever day!

You might also find that using a pool robot to clean the pool is actually better than the service guys because you can run it daily if you like...mine will even pick up leaves without breaking a sweat.

Btw, metals often don't show up on tests, especially in the pool store, if sequestrant is being used. Typically, if you have a stain that doesn't respond to chlorine but does respond to AA then you do have metals that when the ph gets high enough, are released and therefore stain.

So whatever you decide to do longer term, you might want to consider getting a kit and some muriatic acid and at least getting the ph lower...add a couple bottles of Metal Magic and see if that does the trick. Unless sequestered, staining will always come back if the ph gets higher (as long as there's metal in the water.)

 

[jumpinjackieflash]

We do have a Polaris automatic cleaner; it does a great job. We have to empty it twice or three times a day in leaf season! We've got lots of trees and invariably it's windy in the fall and our neighbors also contribute to our leaf load. (It's not fully leaf season yet and this staining started in August, so I know it's not organic.)

The pool service gave the pH at 7.2, but as I said, I can't remember seeing him use an actual dropper test kit, only strips. I know there's no way to estimate the pH that closely using a strip! Does the supply store process usually give an accurate pH reading? Can I get a decent test kit there, or what do you recommend? I've been a bit lax about water testing since we moved to this house - used to do it myself with our other pool. This is the first problem we've had after the pool renovation. I want it to be the last.

Will the CYA ever go down if I stop using pucks? Does it ever dissipate naturally without draining out the water? Is the CYA reading accurate at a supply store? Funny how they didn't say anything about that....

By the way, we never close the pool here in Houston. We can't actually swim comfortably in December and January, but for 2 months of dormancy, it's not worth closing the pool. So this is a year-round proposition.

Oh, p.s. - Should I go ahead and add borates now - since the pH is closer to the right level for that? Had been considering adding them. Or would that cause more problems with the staining?

 

[Swampwoman]

The cya will only go up if you keep using pucks...and quickly...but it generally desnt go down without an outright water change...eg through splashout you might lose five percent or so in a month or to...so not nearly enough. In my area, sometimes winter closure, with snow runoff, you can get more dilution...but not where you are. You efforts to balance the pool and stave off algae become more unreliable at high cya levels so its really worth making the switch.

In your shoes, I'd go ahead and get the full TFTkit ( http://tftestkits.net/splash-page.html ) or the Taylor2006 just so that I could test even if I did hire a service again, and so that your in the position to take control with the new plaster.

With adding borates, while I don't think it would necessarily exacerbate anything, I wouldn't do it the borax-plus-muriatic acid way without a test kit, particularly since the borax raises the ph until you drive it back down with MA.

For the convenience and given your pool size, I'd be inclined to use boric acid instead, which doesn't require MA or a zillion boxes of borax...you can get 55lb containers at Duda Diesl http://www.dudadiesel.com/
Its not much more expensive in the end, especially when you consider the convenience. Its what I use to borate the pool as I'm not in love with handling MA. That said, while the addition typically doesn't net a ph raise, it might raise it a little while its being mixed in, so that's a consideration.

 

[jumpinjackieflash]

So I was going to fire the pool service guy today...But he didn't show up! He sent his assistant today, and hasn't answered my texts. He might be out of town but it would have been nice to have known that. He had no idea I was going to confront him, so he's not hiding from me...

I made 2 phone calls to other service companies and they will come over today or tomorrow to see what's going on. I am not necessarily going to hire one of them, but I want to see if either has a clue when it comes to staining. One of them is already behind the 8-ball, because I mentioned the ascorbic acid tests and he had no idea you could do that. I will have to get a sump pump to drain out some of the water, I suppose about 1/4 or even 1/2? Someone needs to find a way to degrade CYA without draining the pool! Come on chemists!

I'm not excited about taking care of this pool by myself. Since we are open all year round, that means every day maintenance. I know most of you really enjoy this, but with 43,000 gallons, that's still a lot of bleach to add daily. I haven't found a cheap source of 12% bleach. Even regular bleach costs $3 a gallon at the grocery store. I don't mind keeping an eye out, but have never learned to do a backwash or add DE. Our last pool had a cartridge filter. I *can* learn, and I'm probably going to need to, since I can't imagine any pool service that doesn't use pucks. How could they stay in business if they had to visit pools every day?

Well, I need to get a test kit and see if my pH is really 7.6. That's going to take another week or so, unless I can get one locally. I'd really like to get something into the pool to start working on those stains...Can I go ahead and put sequesterant in without worrying about the CYA at the moment?

Oh, and one more thing - if I partially drain the pool, do I risk getting algae due to turning off the pump for a day? I think my FC is high enough, but I don't want to destabilize other elements until I can get the CYA down.

 

[jumpinjackieflash]

Alrighty...Pool Service Co. #1 was just here. Their opinion is that it is scale, and I should buy 2 bottles of Scale-Tec and throw it in the pool ($35/20,000 gallons). He said that the Jack's Magic #2 is more for spot treatment (which is true) and it wouldn't work for the scale, which would just reappear even if I treated it. I mentioned metals and he said he doesn't think that is what is going on. But would Jack's Magic #2 work on scale? The spots are still nice and clean where it was applied.

He also said that a CYA of 100 isn't anything to worry about.

The surface of the plaster is not scaly at all. It feels about as smooth as it ever has. I actually wanted him to give me a quote on what his service would cost, but now that I have spoken to them, I would probably not use him anyway, so...

 

[Swampwoman]

He also said that a CYA of 100 isn't anything to worry about.

Warning, Will Robinson, warning

I'm afraid you're at a juncture here. I'm not trying to "push" you to adopt our tfp/diy methods, but will say that on this forum to receive useful assistance you've kinda gotta follow one path or the other...mixing the advice just doesn't work (you are correct that service techs cannot generally use unstabilized products...hence a completely different methodology must by attrition, reign )

The second red flag about the tech is the suggestion that you don't have metals when you tested with the equivalent of ascorbic acid...I suspect instead that you have a bit of metal WITH scale, which makes it a bit trickier to manage.

 

[jumpinjackieflash]

Thanks for the response. I'm not trying to mix the advice, it's just that you guys aren't here to see the pool, so I am seeking some local eyes to know what to do next. You must understand that the TFP method (used to be BBB) is overwhelming to consider at first. When there are problems, it's even more overwhelming to be told that I must obtain a test kit first, and take over the care of the pool before addressing the staining (which now might be scale). I guess the staining hasn't gotten worse, but it hasn't gotten better either. Every week that goes by, I worry about the ultimate effect on the plaster.

I will do all of this, although I am admitting that I am daunted by the size of our pool, how much bleach I will have to keep on hand, and having to learn how to deal with a DE filter. Does anyone here have such a large pool?

The current pool service co. guy is out of town for a week (great timing!) but his assistant will come by tomorrow, drain some water out, and add some more sequestrant. He wants me to wait until after that to see what happens. I guess I will see how it looks, but if it's scale, it will come right back, correct?

 

[Swampwoman]

I think Dave's pool (TFP moderator) is the same size as yours. Maybe he will chime in.
Because my liner is vinyl, I don't know a lot about scale...but my understanding is that if your chemistry parameters are not in balance, yes, scaling will continue. So to ultimately control it requires understanding, tweaking, and dosing...which again points to more hands-on over site.

In Pool School I believe there is an article that talks about CSI...calcium saturation index. Have a read about that to garner a base understanding of what causes scale, then play around with the pool calculator to see the different effects additional have on your CSI. This will not be wasted time even if you hire a tech, because you'll be informed on the subject and they won't be able to fib to you

Re liquid chlorine...my pool is 22-23k. In the summer, I use about 2 ppm a day to keep my level above 6 with a cya of 40 so that it never drops down below 4 ppm even with lots of sun/bathers....eg roughly half a bottle of 12%. Every pool is different, but for me, I buy 2 cases of 12% (8 jugs) in recycled containers twice a month. Not a big deal for me, compared to the kind of hassles I see other people go through fighting algae

In your shoes, I'd just but 4 cases every 2 weeks...that's really the only difference. I'm guessing you'd just add a bottle a day...FYI, my pool co. Is also a builder and tech. If I want to have them out, they bring me the cases. I get my own because life is easier if the techs are only involved in mechanical or opening, etc. that's because my methods are different. But maybe you could get a tech to make a 2x/mo visit to check filter, etc., deliver your chlorine, and make a rule about no stabilized products/no mystery additions...just help out as directed.

With the de filter, mine is sand, but there are lots of threads about how to maintain. Hope that gives you food for thought/further reading/ideas.

 

[chem geek]

The biggest hassle for a large pool is the weight of chlorinating liquid needed. A 4-gallon case of chlorine weighs around 39 pounds (for the chlorine -- the bottles and case add to that). The suggestion to have a tech deliver the chlorine and do some other cleaning tasks would alleviate that hassle. Pool services normally don't use chlorinating liquid because they typically only visit once a week, but if you were to just add the chlorine every day or two, then they can just deliver it to you in bulk.

 

[jumpinjackieflash]

Finally! I got my test kit and have done 3 tests so far.

CH is 425
TA is 90
pH is 7.5



The pool guy is trying to get rid of the (what I now believe is) scale and has put Jack's Magic into the pool. It looks better but I am going to do the tests and just check things out. Should I adjust the CH or not yet?

p.s. It's been a while since I had a test kit and I'm enjoying it immensely!