Yellow stain - not mustard Algae

[newskate9]

Hi all, new here, hope someone can help.

Pool is in third year this summer. Vinyl, in ground CU ion / CL system, cartridge filter, gas heater............ I love this pool. We have steps in the shallow end, and a bench in the deep end. The bench reaches 1 foot under water, and then makes up the wall to the ledge that surrounds the deep end.

End of summer of first year, start developing yellow stain right under the bench and right under the steps. The stain is on the liner underwater of course - but NOT where there is tape / blocking over the bolt holes of the steps / bench, and NOT where the label is on the front of the bench (under the liner of course.). I cannot remove it. The water is checked daily by me, and weekly I take a sample in - it's just about perfect all the time.

Eventually after trying every chemical they can sell me, it's still there, but not on the table / label spots. The owner (nice guy) comes out and spends 4 hours or so on the stain, standing in the water. He uses stain remover (the granular stuff) and muriatic acid sent down a PVC pipe directly on the stain. 4 hours of that and rubbing and the stain is gone. He does the same to the stain below the steps.

Fast forward to year two. Near the end of the year, my chlorinator plugs and I get an algae problem. I get that fixed and all is well - but shortly thereafter, the yellow appears again. I try just scrubbing it - but no help. I close the pool and decide to deal with it this year.

I opened the pool, the stain is still there of course on both units. The water is just about perfect and as soon as I warm it up a bit, I'll jump in and try to scrub it.

So the questions:

1. What is it?
2. Why only where the labels aren't? Does this mean the stairs / bench were not cleaned before installation and something is leaching throught?
3. What is this cleaning doing to my liner?
4. Anything I should try that could clean it without lots of time, lots of scrubbing and without damaging liner?
5. Other input?

Thanks for reading and any help!!

[newskate9]

Bump.

Come on you experts!!!

[steve767300]

Hi, we had the same problem and got rid of it by keeping the chlorine level higher(3ppm). After about a month of higher chlorine level, all stains disappeared.Hope this helps!
Cheers
Steve

[Shdak]

NOTE: some algaecide's can cause yellow staining, not sure what the trigger is that sets this off, but I have seen this happen with my own pool when chlorine level fell below 2.

I recommend keeping chlorine levels between 2 and 4 to help prevent this from happening.

[Door]

I have a yellow stain as well and I know what caused it. I used an algaecide and the next day there was a yellow stain on the wall from my return line all the way around to my skimmer. I also forgot to switch the pump from auto to manual. So it only ran for 3 or 4 hours, which may have helped to cause the problem.

I am stuck with two issues. Due to all the rain we have been getting, my water was way too high when I put the algaecide in The water was above the skimmer and the skimmer couldn't skim (only pull in water).

So now I am stuck with yellow both above and below the water line. Any idea how I get rid of the yellow stain that was caused by the algaecide? And if it is a water treatment, what do I do about the stain that is above the water line? All the stain treatments talk about removing mineral stains. None of them mention anything about stains from algaecide. So I'm at a loss as how to correct the problem.

[mr_clean]

if its just a yellow algae stain keeping your chlorine level high and scrubbing will remove it.
if it's from metals in water you can use a sequestering agent/metal remover that come in qt bottles. If metal level is real high more than one may be needed with some scrubbing.

[suebhaven]

I have the same problem. I cannot remove those d....ed yellow stains for anything. They are mostly around the side of one side of my pool and also on the bottom in spots. I tried dumping a container of oxalic acid in per the pool guy's suggestion, but it didn't work. I bought a smaller quantity and scrubbed a small section and it did work, but a week later, the stain came back. It doesn't matter how high or low I keep the chlorine, they just won't budge. I have had my pool for 13 years and have never had this problem before.

Any help would be appreciated

[chem geek]

It may be iron stains. I had some mounts to stainless steel bars just below the waterline rust when a Trichlor floating feeder parked itself too close 7 years ago and I'm still paying the price from the rust and iron in the water. When the pH gets too high (above around 7.8 or so) the plaster can turn yellow in some areas. Lowering the pH helped clear it up as did using a metal sequestrant. Ascorbic acid also helps, but the stains can still come back unless metal sequestrant is regularly added so instead I just make sure the pH doesn't get too high. Read Metals in the Water and Metal Stains.

[phoys]

HI,
I have the same on my pool - but mainly above the water line, Although sometimes I get the odd stain on the pool in certain places.
It seems to be Bromine related and its quite a greasy yellow deposit. I'm not sure if its the Bromine sticking to suncreams that our family use - But its not easy to clean - and doesnt totally clean off.
The deposits seem to increase if the cover is left on for a couple of days.

Pete