Our Swimwear Is Turning Green In The White Areas. Why Is This?

by Rachel

We have had our swimming pool for 1 week and have noticed that all the white areas and on the lining of the pool have turned a greeny yellow.

We use a chemical floater to which 3 chlorine tablets are situated as this was the only way to get chlorine levels up. I've managed to balance it but then the levels drop really low.

Thanks for the question Rachel

I'd like to have your complete chemical readings:

Chlorine, CYA (cyanuric acid/stabilizer), pH, Alkalinity, Calcium Hardness, and Metals (iron and copper).
It makes troubleshooting much easier and the process of clearing up your pool will go much faster.

You can get this done at your local pool store.

I'd encourage you to get a Taylor FAS-DPD K-2006 pool test kit.

Pool Water Testing

Water Testing Kit

Without these numbers I'm just guessing at what the problem is. It could be high metal content in the water, but that's just a guess. When I get the chemical numbers I'll know for sure.

Get back to me with the numbers and I'm sure I can help.


Comment By Rachel

I have just tested the water and this is the reading:

total alkalinity 120ppm
pH 8.4ppm
free chlorine 10ppm

I hope that this can help. I'm beginning to think about taking it down as I feel I'm fighting a losing battle with the pool unless you can help me. Having tested the water now after shocking the chlorine strip is a blue green and doesnt match any of the colours on the bottle why is this.

Could you also tell me how to keep the water crystal clear?

Kind regards


Comment By Robert

Hello again Rachel

I still need the CYA, metals, and hardness readings. The CYA is important because this is the stabilizer for the chlorine. If it's too high or low the chlorine will be rendered less than fully effective.

If it's high you'll need to do a partial or full drain and refill. The CYA test should have been done before the shock because if it is high, you just wasted alot of chlorine.

And did you get the pH down to 7.2ppm before you shocked? Remember, anything above 8.0ppm and you're only using 25% of the chlorine.

I think you're going a bit too fast right now. Shocking is a process, not an event or a name. There's a way you need to do it to maintain the chlorine level of 12ppm.

This requires shocking in the evening and retesting in the morning, and possibly doing the same again, keeping the chlorine level above 12ppm for a period of time. If you shock the pool once you may not have killed all of the algae.

Your chlorine level may drop to zero within a few hours, leaving your pool open to even more algae. This is why constant testing and shocking might be necessary.

I'm telling you this because, since 1999, I've cleared up hundreds of green pools on my pool route in Arizona.

I've also been the pool operator for our YMCA since 2008. This is probably not the experience you'll have access to when talking to the guys in the pool store.

If you can just slow down a bit and get me the other readings the process will go much faster. Keep filtering 24/7 and bask wash once per day.

Test strips can only go so far. The reading you got shows that the chlorine reading is probably high. How long after the shock did you test?

Again, without the numbers I'm just guessing at what the problem is. Let's get the pool cleared up first before we do anything else.


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Jul 19, 2015
Green Stains on Swimwear
by: Alex

Hi Robert, I have a quick question.

I am on vacation with my family and we're renting a villa. After a few days we noticed our daughters swimwear had green stains all over them, then my wife's. We washed them but it didn't come out. We purchased her new swimwear and the same thing happened within a few days. Pool inflatables and tiles around the pools surface level are all stained also. It comes of the tiles and inflatables rather easily when you wipe them.

It also seems to more affect the tiles most shaded from the sun.

The property manager says he brushes the pool every week but we did not seen him until we raised the issue. He insists it's not algae yet it does seem to tick the boxes. The villa owner has been extremely helpful and has a pool specialist calling tomorrow.

I am not familiar with pools or have the materials to be able to give you any readings. Could you tell me if this sounds like algae and would algae stain swimwear?

Thanks for the question Alex. My initial response would be a no for algae. It's organic and can be killed with hot water and soap. If the pool surface doesn't feel slick or the water is not cloudy then it's probably not algae. I can only go this far with the algae theory because I don't have the readings.

My 2nd guess would be copper or some other kind of metal in the water. This can cause white suits to stain as well as blonde hair to turn green. The old myth is too much chlorine but in reality it's copper. You can ask the manager if the pool is filled with well water or does the source water have metals in it. If it does and they're not using a metal sequestrant they're going to have a much larger issue down the road with metal staining. I don't think you're in a dangerous situation but you may want to stay clear of swimming. If not then have designated suits you're going to use then toss them when you're finished.

Hope this helps.


May 18, 2016
Rust Spot In Pool
by: Alex

The bottom of my pool has rusty spots. We had high wind few weeks ago and not sure if from trees buds and leaves falling in the pool or from my neighbor AC unit that drip rusty water. How can I remove those spots?

First you need to determine the kind of stain it is. Place a chlorine tab on an affected area for about 2 minutes. If the stain lightens then it's an organic stain and can be removed by shocking the pool and tabs.

If it doesn't lighten up get some crushed up Vitamin C and place it in a sock on an area. If that lightens up it's a metal stain. You're going to need to do an ascorbic acid treatment. That can be a little tricky as it will increase the chlorine demand temporarily.


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