I'm afraid to ask. What are these stains?

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B

boringforumname

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Oct 15, 2015
25
Kailua, Hawaii
Little background: I have been taking care of my pool solo for 2 little more than 2 years, but haven't been as consistent as I should be. The pool may have had very low TA levels and calcium levels for an extended period of time.

My current numbers are:

FC - fluctuates daily but right now about 9-10
pH - 7.5
TA - 90
CH - 230
CYA - 110

The first 4 pictures are the one I am most worried about. These brownish/orange-ish stains started about 1-1.5 years ago, and started small but kept growing. It appears to be mostly a problem in the shallow end, not the deep, and seen clearly on the grout between the tile. Could this be some form of algae? Metal staining? Grout stripping away?

Please zoom in if necessary. I can upload the pics here in full 3-4 MB detail if it would be better.

http://i1377.photobucket.com/albums/ah55/jwhite6679/IMG_5895_zpsgsqiiera.jpg
http://i1377.photobucket.com/albums/ah55/jwhite6679/IMG_5896_zps4wunegvu.jpg
http://i1377.photobucket.com/albums/ah55/jwhite6679/IMG_5897_zps9ewefxa4.jpg
http://i1377.photobucket.com/albums/ah55/jwhite6679/IMG_5899_zps58t6kcnp.jpg

These second set of 4 pics are another issue. The weird thing is you can see deposits on the tile ABOVE the water line, but below the water line seems to be clear (please ignore the little bit of debris floating on the water surface). On advice our old pool man (before I took it over), I tried scrubbing it with a stone (pumice?). You can see some of the tiles are cleaner in the center but it's impossible to scrape this away around the edges of each tile or in between the tiles.

http://i1377.photobucket.com/albums/ah55/jwhite6679/IMG_5914_zpsiw9li2qa.jpg
http://i1377.photobucket.com/albums/ah55/jwhite6679/IMG_5916_zpssbm2u5z6.jpg
http://i1377.photobucket.com/albums/ah55/jwhite6679/IMG_5917_zpstbjqvvfc.jpg
http://i1377.photobucket.com/albums/ah55/jwhite6679/IMG_5918_zpsyvwopbb4.jpg
 
From my eyes over here on the mainland, you almost appear to have both calcium residue and algae stains going on there. The calcium deposits can often times be removed above the waterline with some muriatic acid and a wire brush. The pumice stone has been used before as well. Below the waterline is a matter of deciding how important it is to you to remove. Some might drain and do an acid treatment. Others may just keep their "CSI" level a little more on the negative side in hopes that time will allow the old scale to dissipate and/or fall off.

The green algae is treated with a "SLAM" link below. How are you testing your water to get those numbers? Since our test kits don't read CYA over 100, we're curious. Your CYA may actually be much higher, in which case trying to keep FC high enough to compensate may be difficult.
 
I used the Taylor 2006, and to get a CYA reading above 100 I carefully use half pool water and half tap water for the 7mm part of the beaker before adding the reagent. Whatever reading I get, I double it since the solution is diluted by half. Then I run it a second time. I always get a reading of about 100-120, with 110 being the most common.

The weirdest part about the stains seems to be it's mostly in the shallow and only on the grout. Since it's an orange/brown is it possible it could simply be erosion or etching? Metal stains?
 
Your current test results don't indicate a pattern for calcium, but it would depend on the testing history for several months. Metal stains like iron can show-up just about anywhere in the pool. You could always take a fresh hose water sample to the pool store to check, or perhaps call you local water company and ask if they show any metals in the water source. As for your CYA, we know it's high. Anything over 90 and it becomes very tricky to manage. While you are maintaining an elevated FC to compensate (Which is good), if that is algae on some spots, doing a "SLAM" to remove it would take a lot of bleach.

I would suggest checking on the metals issue as noted. But I would also recommend you perform an overnight FC loss test (OCLT). That will tell you if you also have algae so you know for sure.
 
Your current test results don't indicate a pattern for calcium, but it would depend on the testing history for several months.
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The Calcium and TA were probably low for 6-12 months, maybe somewhere in the 60-70 range for calcium and 50-60 for TA. The thing is living in hawaii I do not have pool heating equipment, but I don't know what kind of pipes are running underground to the pump. The house and the pipes are probably very old, so there may be copper piping but I have no idea.

Metal stains like iron can show-up just about anywhere in the pool. You could always take a fresh hose water sample to the pool store to check, or perhaps call you local water company and ask if they show any metals in the water source.
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That's a good idea. How many metals are common for staining? Just copper and iron? Does the average pool store have the ability to test for both? I can take a sample or current pool water but that won't tell me if the water in the past may have been to etching. Also, I doubt our municipal water is the problem because the problem only started less than 2 years ago and we've been filling this pool for 40 years with no stains like this.

But I would also recommend you perform an overnight FC loss test (OCLT). That will tell you if you also have algae so you know for sure.
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Will do. The thing is even if I keep my FC at 5-8 I still will battle an outbreak of some form of something, not really sure what it is. I never see green, it's more of a powdery yellowish substance mostly noticeable on the walls of the deep end. I brush it, shock the pool, and vacuum a day or two later and it's gone. This happens at least once every 4-8 weeks.
 
How many metals are common for staining? Just copper and iron? Does the average pool store have the ability to test for both?
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Usually iron and copper. The pool store may be able to give you an idea. Their testing is never as accurate or consistent as we would like, but it may give you an idea.
The thing is even if I keep my FC at 5-8 I still will battle an outbreak of some form of something, not really sure what it is. I never see green, it's more of a powdery yellowish substance mostly noticeable on the walls of the deep end. I brush it, shock the pool, and vacuum a day or two later and it's gone. This happens at least once every 4-8 weeks.
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This is very common with algae, and may even be related to Mustard Algae. Either way, a thorough, properly performed SLAM will eradicate it, but you must perform the SLAM exactly as noted on the SLAM page, and ensure you pass all 3 SLAM criteria.

Let us know how it goes and if the water testing shows any metals. Aloha!
 
I did the overnight FC loss test, and it showed no drop. The local pool store 5 minutes from my house does not do metal testing, and neither does the one they referred me to call. I'm still looking around for someone who will do it.

This is very common with algae, and may even be related to Mustard Algae. Either way, a thorough, properly performed SLAM will eradicate it
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I should take a picture of it the next time I have it, both of the walls and the cloud it produces when it's brushed. When I look up mustard algae pics on the internet, it doesn't really look like the stuff I battle. The stuff I get is more of a uniform bloom that spreads across a wider area. It is thin and actually hard to see unless you look at it from the right angle near the walls of the deep end. Of course if you let it grow it will become really easy to see in a day or two, but at the start it's pretty subtle and I know to shock it right away.

The thing is, when I shock it, I brush the sides and probably only shock it to about 10-15 ppm FC. Then vacuum a day or two later and it's gone. Based on your the chart here http://www.troublefreepool.com/threads/2177-Chlorine-CYA-Chart and my CYA levels, I should have t shock it to 60-70 ppm. In the 2+ years I've been taking care of the pool I doubt I've shocked the FC over 20ppm. Is it possible it's not entirely dying? Or that's it's not mustard algae but something else?
 
Is it possible it's not entirely dying?
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I think that's the key right there. That's what makes a "SLAM" so much different from a typical "shock" you hear about around town. The SLAM is "maintained" until your water passes all 3 criteria on the SLAM page (link below). That's extremely important. While you appear to have passed the OCLT, your other descriptions sound like algae, especially when it fades or disappears briefly with a little extra FC. I would give the SLAM page a try. Make sure to do everything listed on it. If that's algae, the SLAM will kill it so that your can backwash the dead residue out.
 
The thing is I already have 3 out of 3 criteria. The pool water is always clear, and even when I get a small bloom of algae the water usually remains clear (but that may be because I kind of overdo my filtration with my pump running longer than it needs to). Every time I test for CC it's usually zero, and I just passed the over night FC loss test.

I'm considering the SLAM just in the hope that those stains may be algae related, but they really look metallic to me. When it comes to the SLAM, I have so many questions, I don't know where to start. These are just a few, but I'm sure I'll think of more.

1) Some of these may seem silly but I'm kind of a worrier, so please bear with me. Are there any risks involved in raising the FC to levels that high (either recommended shock levels, or yellow mustard shock levels)? Should I keep my kids out of the back yard until it comes down, just in case they accidentally fall into the pool? Will the pool give off noticeable fumes with chlorine that high?

2) I worry about this statement on the SLAM page "Higher FC levels will oxidize contaminates more quickly, but levels that are too high can cause damage to the pool or the pool equipment. " What are the common concerns? Could it bleach, etch, or in some other way destroy my tile or grout? Possibly strip or clog components? Other?

3) Under a hot hawaiian sun, and at my current approximate 110 cya level, how long do you expect the chlorine to come down to safe/swimable level and what would that even be?

4) Can I use Cal Hypo to SLAM? The pool store 5 minutes from my house does not sell liquid chlorine, if you can believe it. Regular 8.25% Clorox is about $3.50-5.00 per gallon on the shelves (OUCH!). I can buy 2 gallons of 10% liquid chlorine for about $7.19 at my closest home depot (20 mile round trip, adding cost), but that comes to a cost of about $1.22 per ppm in my 35,000 gallon pool, not including gas. The pool store 5 minutes away does sell cal hypo of course, which is about $14 for a 5 lb jug. That works out to almost exactly the same ppm cost as the home depot liquid chlorine!! (Please correct my math if I missed something) So....can I SLAM using cal hypo? Other than the addition of CH are there any other potential problems?

5) Based on my above issues would you recommend I SLAM to regular shock level or mustard shock level? Those mustard numbers are crazy!

6) The last time I raised FC by 8-9 ppm using cal hypo by pH went from about 7.5 to 7.8 or so over night. If I needed to raise it by 25-60 ppm I could drive the pH well over 8 (9? 10??). How low should pH need to be to start? Or should I raise the FC by say 5-15 ppm per day adding muriatic acid as needed to keep pH in check? And even if I did that, how can I trust the pH test readings when they say it's going to be unreliable if FC is high?
 
It is safe to swim in your pool with FC up to shock level for your CYA, Chlorine CYA Chart. We swam last summer every day during a SLAM with FC at 28 and CYA at 70.

The concern about chlorine levels above shock level are mostly with bleaching out colors on vinyl liners. And there is to reason to have it above shock level anyway it doesn't help anything.

It is safe to swim with FC at 40 and CYA at 110.

It is fine to SLAM with cal-hypo as long as your pool can take the extra calcium. High calcium leads to calcium scaling, Pool School - Calcium Scaling

The only reason to SLAM at mustard shock level is if you have mustard algae, Pool School - Mustard Algae.

Cal-hypo doesn't raise PH. Your PH went up for a different reason, aeration, high TA. The instructions for a SLAM say to lower PH to 7.2, Pool School - SLAM - Shock Level And Maintain
Muriatic acid does not raise FC, it lowers PH, Pool School - Recommended Pool Chemicals.
The PH test is not valid when FC is above 10 ppm.
 

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That whole pH test not being reliable above a FC of 10 really concerns me. If you have higher cya levels, like I do, and consequently have to keep FC above 8 and really near 10-13 anyway, then it's almost like you will never get a reliable pH test, and regular pH testing is the second most important test to do on a very regular basis right? Do high FC levels give a higher false reading or a lower?
 
Usually higher, but that isn't consistent. Yes, it is a big problem, you will have to let your FC drop to 10 regularly to rest PH. That is one of the main reasons we recommend partial draining of the pool to lower CYA. And SLAMing requires a tanker load of bleach.
 
So in your experience both with your own pool, and/or pools you service and time on this forum is there any significant risk to pool equipment, tile, grout, piping, etc when performing a SLAM with higher cya levels?

As far as the mustard algae question that was mostly based on the earlier part of the thread. I get this powdery algae that's yellowish and always blooms on the deep end walls first. I brush it, shock, vacuum a couple of days later, and it's gone. However, Texas splash was concerned it may be related to mustard algae and maybe I'm not completely eradicating it. If I keep my FC up, it stays away for weeks at a time, but if I let the FC drop below 5, even for a day I can usually expoect a bloom. This happens once every 3-6 weeks. That's why I'm not sure whether to SLAM to the mustard level or the regular shock level. If it is some sort of mustard algae that is kind of being kept at bay but not eradicated, I wonder if the mustard level shock would be more appropriate just to be sure. This yellowish, powdery algae that brushes easily off the walls (even before the shock) is really the only form of algae I ever fight. My pool never goes green no matter what the weather, and the water is almost always clear.
 
Good morning "bfn". :) I think after going through all the notes above, we inevitably come back to the basics ..... overall water chemistry. When it comes to algae (any type), the reason it found a home in a body of water is because the FC/CYA ratio was not balanced as noted on the Chlorine/CYA Chart. For many, they got caught-up in their daily chores and didn't notice the FC fell below their minimum FC level for that current CYA. For others, they used pool store products for so long that their CYA exceeded the TFP recommended level which demanded a much higher FC. Not only is that tough to do accurately when the numbers exceed what is listed on the Chlorine/CYA Chart, but it becomes tricky in our daily lifestyles. As you learned above, it also makes testing pH tricky since a high FC (over 10) can skew the normal pH testing process.

So what do you do now? Ideally ... lower the CYA a bit. Once it's lowered it will NEVER increase again unless you chose to increase it on purpose - either by adding stabilizer or a chlorine product that has stabilizer added to it (i.e. chlorine tablets/pucks, bags of shock). Otherwise, it will not go up again on its own any more. Lowering the CYA would resolve most of your issues and make chlorinating/balancing your pool for sanitation and algae prevention much easier. It also resolves your pH testing concern. You might also find yourself using less bleach which is obviously an issue for you there in the Kailua area.

You know you need to SLAM as well to kill the algae once and for all. A regular SLAM kills just about all types of algae. After the SLAM is complete, only then do you increase FC to mustard algae levels, and only for 24 hours. I know you said before you passed the 3 criteria, but the kicker here is you can still visually see algae. Sometimes, especially in it's early stages before making water cloudy or green, the algae doesn't appear to effect a lot of things chemically, it's just a nuisance. That's also why many people go through that vicious back & forth cycle - here for a week, gone for a week. Unfortunately, liquid bleach is the most efficient method to chlorinate during a SLAM. It can be generic bleach, just look on the label and it should say "Sodium Hypochlorite" and have a percentage on the bottle (i.e. 8.25%).

One other thing ... your low CH. I was chatting with another islander whose CH was exceptionally low for a plaster pool. There's a concern for their plaster etching and dissolving away from the sides when the CH gets too low, either because of the soft water locally or constant rain and water exchange. So be very careful of that as well okay. Your CH should be no lower than 250.

I hope we've given you some good info to go forward on. If you still have a question or concern, just let us know and we'll try to help you out.
 
Thank you all for the info so far. It's been really excellent.

Texas Splash said:
So what do you do now? Ideally ... lower the CYA a bit. Once it's lowered it will NEVER increase again unless you chose to increase it on purpose - either by adding stabilizer or a chlorine product that has stabilizer added to it (i.e. chlorine tablets/pucks, bags of shock). Otherwise, it will not go up again on its own any more. Lowering the CYA would resolve most of your issues and make chlorinating/balancing your pool for sanitation and algae prevention much easier. It also resolves your pH testing concern. You might also find yourself using less bleach which is obviously an issue for you there in the Kailua area.

You know you need to SLAM as well to kill the algae once and for all. A regular SLAM kills just about all types of algae. After the SLAM is complete, only then do you increase FC to mustard algae levels, and only for 24 hours.
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I know I should bring down cya levels, but I'm not sure how low I should go, or how low is even practical. I live in a very sunny area and my pool is fairly large at about 35,000 gallons. I should probably make a different thread for this part, because the math gets really interesting.

About the SLAM, just to clarify, I would bring the levels to regular shock level, hold it until I pass all 3 criteria, and when it's passed immediately bring it up to the mustard shock level and hold it for 24 hours (all 3 criteria should still be true) then allow the chlorine to drop? Not to complicate things further but I just noticed I may have some very small spots of black algae. From what I've read that is the worst one to fight. Will the mustard shock level kill it? Do I need added chemicals or anything else?

[h=2][/h]
 
I'm assuming it is very sunny where you live, so a CYA of around 50 would be good. If you have 100 now that would (obviously) be a 50% water exchange. 30 is better for a SLAM, if that's what you plan to do.

If you have occasional blooms that doesn't sound like mustard to me, so after you pass all 3 criteria you simply allow the FC to drop to your target level and continue to test and adjust based on whatever CYA level you end up with. Start with regular old SLAM, it's very rare to see the mustard variety.

I would suggest reading this over and over and over Pool School - SLAM - Shock Level And Maintain
 
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