Closed pool with Iron Stains + Pink Algae... Now What?

Last year I was fighting iron stains (yellowish stains that disappear when a vitamin c tablet is placed on them) and "pink algae" (actually bacteria?) when I ran out of time and closed the pool in early September. Now it's that time of the season again I need to deal with these problems.

I am hoping that shocking the pool when I closed it and shocking it again along with vigilant brushing of the walls/floor once the cover is off will take care of the pink bacteria. However I have some concerns since I'll have to let the free Cl drop (or keep it low to start) to get the metal stains out.

To get the metal stains out, I understand that one needs to lower the Cl and pH, add asorbic (vitamin C) or oxalic acid to the pool to remove the stain from the liner and suspend them in the water, apply a 2-3x dose of a metal sequestering agent (metal free?) to "gather them up" then slowly bring up the Cl and pH.

Perhaps startup is the ideal time to do this since Cl and pH are likely to be low to begin with but I'm a bit worried that the pink bacteria may come back if I leave the Cl level low while I'm removing the iron stain..

Oh... and to complicate matters a bit I plan to switch to the 3 Bs (Bleach, Borax, Baking powder) this year. So I'll need to adjust CYA prior to sanitizing with the bleach as well. So many steps I'm a bit overwhemed. Here's the order I think I'm going to approach this.

day 1
test water
start up pump/filter (cover on) run continously
adjust Alkalinity
add polyquat
add asorbix/oxalic acid

day 2
add metal free

day 3
backwash filter
adjust pH
adjust CYA
put pump/filter on timer

day 3~10
adjust Cl up slowly
keep eye on CYA

day xx
remove cover

Anyone have suggestions for my approach?

Hi, Lee,

You have obviously thought long and hard about your process. I would interject that, once you start, test and post your numbers here on the forum daily. That gives everyone a definitive point to start and will result in the best advice from the forum along the way.

I am assuming you cannot drain and refill. That would certainly be the most bulletproof way of getting your metal out. Do you have an idea as to how it got there? If you refill from the same source, you will eventually have to do this battle again.

P.S. I, and others on this forum, are not big polyquat advocates. I've only used CL and have been successful to this point. I think I understand why you're using it but Ben seems to think it works much better as a preventative than a cure.....Pricey, too:) :)

Dave S.

I think the use of polyquat here is a good idea, especially when operating with lower Cl levels. It'll provide a bit of insurance for you. However, with you being upstate, it's prolly still kinda cool there, so you most likely won't have to worry about a bacterial/algae bloom. It should work out fine for you.

Michael

Quote:

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Originally Posted by duraleigh

Hi, Lee,
You have obviously thought long and hard about your process. I would interject that, once you start, test and post your numbers here on the forum daily. That gives everyone a definitive point to start and will result in the best advice from the forum along the way.

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Will do...

Quote:

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Originally Posted by duraleigh

I am assuming you cannot drain and refill. That would certainly be the most bulletproof way of getting your metal out. Do you have an idea as to how it got there? If you refill from the same source, you will eventually have to do this battle again.

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Absolutely no idea... there's no metal/iron anywhere in the pump/filter system. In 2004 I was a rookie pool owner and I put a lot of poolstore junk into the pool but I do not recall iron content in anything I put in. The previous owner of the house put the pool in so I am not sure if iron wasn't a problem before I got involved.

I fill with tap water (city water). I will test it and pot the results here as well as my pool water.

Quote:

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Originally Posted by duraleigh

P.S. I, and others on this forum, are not big polyquat advocates. I've only used CL and have been successful to this point. I think I understand why you're using it but Ben seems to think it works much better as a preventative than a cure.....Pricey, too:) :)
Dave S.

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~$15/quart at Home Depot and Kmart is the best price I've seen. I'll add some initially when I'm doing the iron removal procedure since the FC will be low.

Also keep in mind that the CYA dissolves VERY slowly and can take up to a week or more to completely dissolve and reflect accurate test levels. Don't add more CYA or backwash your filter for at least 4-5 days. Remember that it's much easier to sneak up on your target CYA number than it is to overshoot it, because drain/refill is the only way you're gonna bring it back down...

Janet

I think you better find a pool store that can test for iron and take 2 samples with you. One from the pool and one from your fill source.

If the iron is coming from the fill source and there is a lot of it you may want to consider tanked in water or directing rainwater into the pool. Likely need and extra dose for bleach after each rainfall but a lot cheaper than tanked in water.

Got a heater maybe ... with an iron heat exchanger ??? That could be rusting out.

Last year I closed my pool with iron stains. When I opened it they were gone. So I would see if they are gone first. Then I would kill the pink bacteria first if you still have it by overloading chlorine. Once you are sure that the pink algae is gone - then you can work on the iron stains - because you can't keep a high level of chlorine when you are battling iron stains. I would do the bacteria first before I worried about anything else. Once that is gone, then you can lower your chlorine, do the stain treatment, then balance the water. You should be good to go - if you open to no iron stains, you may just have to deal with the algae, if you do - make sure you put in metal free before you do anything else. Keep your filter running 24/7 till you are sure all is clear.

Marie

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Originally Posted by mbar

Last year I closed my pool with iron stains. When I opened it they were gone. So I would see if they are gone first. Then I would kill the pink bacteria first if you still have it by overloading chlorine. Once you are sure that the pink algae is gone - then you can work on the iron stains - because you can't keep a high level of chlorine when you are battling iron stains. I would do the bacteria first before I worried about anything else. Once that is gone, then you can lower your chlorine, do the stain treatment, then balance the water. You should be good to go - if you open to no iron stains, you may just have to deal with the algae, if you do - make sure you put in metal free before you do anything else. Keep your filter running 24/7 till you are sure all is clear.
Marie

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??? I was going to do the exact opposite since the condition the pool is in presenty (sat for the winter with occasional algaecide and bleach) is IDEAL for getting the metal out. Low pH and low FC.

Once I have the filter hooked up and running, I was going to treat it with Ascorbic or Oxalic Acid (Vitamin C or United Chemical Pool Stain Treat) then immediatedly with Metal Free. Once I hit it with a healthy dose of Metal free, I may modify my plan with some skimmer sticks. This way I the Chlorine forces the metal out of the water it'll stain the filter/plumbing.

If I treat the Pink Bacteria first, I would have to drop the FC to remove the iron and that makes me very nervous. I plan to keep the FC up fairly high and shock 1x/week once I'm sure the metal stains are indeed gone until the weather is warm enough to swim.

I understand that the water is ready for stain treatments, but if you have to kill the bacteria by using very high levels of chlorine, the stains will return even if there are traces of metal in the water. You will then have to do the whole stain treatment again, which is costly and hard to return the water to balance. Therefore I still suggest killing the bacteria first. Pink algae is hard to kill, because it gets in the lines, and I had a friend who had it behind the light of her pool. She finally got rid of it by using high chlorine for at least a week. My experience with staining is to make sure the water is free of any algae, then either use something that removes chlorine, or in my case I just waited a little and when the chlorine was around 1 or 2, put the stain treatment in. It will take the chlorine away - it will use a little more of the treatment, but that's all. Once you put in the treatment, put the metal free in right away. It will not take long for the metal to come off the pool, but it will take a while for the metal to get out of the water. After a day I would put a chlorine puck in the basket so that the stain will come off in the filter. I would keep the filter running 24/7. I always dose with a second dose of the metal free, then I start to bring up the chlorine - using the puck in the basket, and using regular bleach too (not in the basket). It can take a while for the chlorine to stabalize, because the chlorine will get used up while it is getting rid of the metal in the water. It is also hard to keep the ph where it needs to be, because the stain treatment is very acidic. It is important while doing the stain treatment to keep the ph as close as you can to 7.2, not higher or lower, you will find it hard to get the water balanced right after a stain treatment for a while. When you see the water holding the chlorine, and holding the ph, then you have the metal out of the water. That is why I say to get rid of the bacteria first - because if you don't have the bacteria out, and then have to use high levels of chlorine and you get stains back, you will have to do the whole thing over again. I had this happen to me, so that is why I gave this advice. You know your pool better, and all pools are different - If you don't have much staining, then your way may be better for you.

Marie... You make some god points... So essentially once there is iron in the water it's darned near impossible to remove it completely enough to prevent staining ever again. So does this mean that even after I do all of this I should never "shock" my pool again? So am I basically doomed?

I don't think it is as bad as all of that!!! I don't know where the iron comes from, I have been trying to figure that out for 6 years. I do know that once I get the pool treated and balanced, I usually don't have any more problems. If you keep up with your chlorine, you never need to shock. That is what I try to do - keep up with the water. Fiberglass pools are actually very easy to keep - there aren't any rough surfaces to get algae in. The most important thing is to keep your ph around 7.4- 7.6 - not higher. I also run my pool with a cya under 50, so I don't need high chlorine levels. I use regular bleach, baking soda, and borax. The only other chemical I use is the metal free (and ascorbic acid if I have stain). If I ever do have to shock, I put a puck in the basket, and use regular bleach in the pool with the filter running all the time. The high clorine levels will drop out any metals that are in the water, so by keeping the filter running with a puck in the basket, the metals in the water will stain the filter instead of the surface of the pool. It seems that when the water stands (filter off), is when the stains grab onto the surface of the pool. I think a lot of pools have stains, but the white fiberglass is more suseptible and the stains seem to show out so much. Once you get used to your own pool, and your water (it is all different) you will be able to keep the pool so easily. This will be my 7th year with my pool, and it really is simple if kept up with. My family laugh at me, because I actually love "pool maintenance".

Though Marie makes lucid and convincing arguments for getting the algae out first, it seems better to address the metal first. The swim season isn't close, at least here in Ct., and once the metal is out of the pool, it's only a matter of days to kill that persnickity algae. I'd also wait to add the cya until the big backwashings (from metal removal and algae destruction) are finnished.
As a side question - why not put a powerful magnet in the skimmer to remove iron? Wrap it in plastic, so it won't rust, and let it pick up the iron ions.(OK, maybe they aren't ions, but I couldn't resist the alliteration :) )
Finding out where the iron is comming from, though, sounds like the best first course of action. If it's the water supply, and you can feasably do it, drain the pool and truck in non-iron water. If you can get all the metal out, you've all but won the battle, just a little high cl for a week and pinky's gone. An added bonus is that you can start fresh, chemically, and get all your numbers where you want them.

I understand your logic. I can only go by my experience - I tried logic with the stains, but it got me no where. I then decided to figure out what was the best way to keep my pool stain free. I tried to find out where the iron was coming from - my water tests that there is no iron in it. I still get stains.... So I just treat the water at the beginning of the season - with metal free before I add the chlorine and balance the water. If I get stains, I treat them, but I find that if I keep my water balanced so I don't have to shock, or run high chlorine levels, I don't have problems with stains. So this was just my advice - I don't promise that it is right, or logical. I just gave my experience on what I did, and what I thought was the best and cheapest way to go.

I'm not sure what pink algae is. Could it possibly cause pinkish stains from the waterline up to the pool deck. That is what I was greeted with when I took the winter cover off my pool.(30,000 gal vinyl lined IG)
If it is pink algae, why was there no slimey stuff , just stains? Scrubbing and an enzyme cleaner had no effect.
Please help if possible!!

Pink algae does wipe off, so I don't know what it could be. Do you have any problem with orange dust that may have gotten under your cover and stained? You can tell if it is a mineral stain by rubbing some ph down, or a vitamin C tablet on it. If that takes it off then it is a metal stain. If it is algae then chlorine should kill it. Some things like leaf stains, and stains from vegetation take some time to lift off, but with the regular use of chlorine in your pool you should see it fade over time. Hope this helps.

An FYI for iron stains...

I had mystery iron stains cropping up last year, mainly on the steps and around the bottom of the liner, where the wall meets the floor. I treated and removed, but they are back upon opening this year.

Due to a new leak (I let my husband scoop leaves--don't get me started), I removed the light fixture to check the gaskets for leakage. I could not believe the amount of rust inside the housing! I had my service guys over replacing the sand, and they mentioned that acidic conditions could cause the rust. Now, I am VERY careful about keeping well-stocked with Borax and Ph levels up. However, the man who sold us the house never was--I know this because we had to replace the liner that wrinkled ALL OVER because of the low Ph levels.

Anyway, you might want to check that light, especially when there seems to be no other source of the metal stains.