The water remains green, no matter what

[reflux212]

Update 1: Thanks for the reply. I'll revert within 24 hours with all the info asked. I figured it might be necessary. (I have corrected the grammatical mistakes, I was typing via my phone's keyboard)

2: This is a 10000sqft commercial pool, 4ft depth. That is a LOT of water to change each time. It was done just a month ago

2.1: The filteration plant is an Astral Pool Volcano High Rate Sand filter (Filter Diameter 1200mm) X 3 nos.

3: Please also look at it in the angle of sabotage, is it possible?

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Hi guys

I was searching the internet for answers when I stumbled upon this gem of a forum.

I have had this pool for nearly 8 years and it has been flawlessly maintained. Recently the water mysteriously turned green. We tried everything but to no result.

Eventually we drained the water, cleaned the tiles and refilled water.

This was 1 month ago, but now the water has again mysteriously turned green. Whenever chlorine is added it turns green...

The only thing I can see different is that the sand used as filter was changed before this issue began...

What do you think the problem is?

Note: the blue gradient in the bottom right of the image are the dark blue pool tiles

This is the water as of right now

Below are the reports from last month before the entire pool was emptied and cleaned. The well water was being used to refill. Its a natural open well that used to have close to drinking water once upon a time.
I have also attached the swimming pool water report for you to gauge the effect the filtration plant has had on the water.

 

[JohnT]

Welcome to TFP!

We really need good test results to give accurate answers. Generally water that turns green upon adding chlorine is caused by the presence of iron in the water. The chlorine oxidizes the iron which turns it yellow, and against a blue pool surface the water looks green. Your picture really doesn't look like that's the issue since the water looks both cloudy and green which is generally algae from insufficient chlorination.

 

[Texas Splash]

Welcome! Wow, that IS green. Along with John's notes, I might recommend the following:
- Update your signature with all of your pool and equipment info. Also include which test kit you use.
- Hard to tell from the picture .... is this an indoor or outdoor pool? Public or residential?
- You might try to find out and tell us what chemicals the pool guy typically has been adding to your water. Things like tabs/pucks, algaecides, pool-specific products, etc. Some of that history might help.

 

[ajw22]

Where do you get your fill water from and have you tested your fill water?

 

[woodyp]

That looks like a commercial outdoor pool to me. And 32 months ago is not "recently". We need GOOD test results to give GOOD advice. TFTestkits.net

 

[reflux212]

Hi guys,

I have updated details in the original post.
At this point I am kind of certain that its because of the iron content in the water as JohnT has mentioned.
I am thinking of putting a water softener.
Any other theories or ideas welcome.

 

[aussieta]

place a skimmer sock and white filter material if you have some in the skimmer basket
after 1/2 to 1 day see what colour it goes

 

[duraleigh]

It is iron,almost 100% sure.

It will be quite an undertaking to get a softener to treat 300k of pool water.

How do you apply the chlorine? If you can slow that down to a steady trickle you MIGHT have some success, Changing your source water is by far the most preferable but I have no idea that's even possible.

 

[reflux212]

Hi

It doesn't seem like iron in water is causing this issue. Because if it was iron, the pool water report attached here in would have had high quantities of iron.

Attached is another test. This one was done just recently. Disregard the label, well water is wrongly entered - it's the swimming pool water after filteration. See the iron level... But, the water (in small quantities was yellow and in the pool was green when tested.)

What else can it be? Or am I understanding something differently.

 

[JohnT]

Iron testing in chlorinated water can be tricky because some test methods don't detect iron that has been oxidized. I'd suggest you have your fill water tested or verify that the test method uses HCl to reduce the iron before testing. Your result shows iron present, and yellow water that looks green in the pool is a classic symptom of iron.

 

[zea3]

My bet is also on iron in the water. If you have any blue tiles or plaster along with the yellow water it will look green in the pool.

 

[jatkinson]

Imagine the bill to SLAM that sucker! He would buy out 20walmarts worth of cheap bleach.

 

[reflux212]

Hi guys

Thank you for the prompt suggestions.

The real issue seems to be the water, it seems to react to any rapid introduction of chlorine.

For the last two months my team has been slow introducing chlorine and we have changed the element in all our water filters - due to this we have no problems anymore.

There was algae formation on the pool floor so we have changed it to 60% sprinklings of Liquid chlorine and 40% chlorine crystals to kill all tiny floor growths.

It has worked well for us.

Key is slow intro liquid chlorine (less quantity and higher frequency)

 

[reflux212]

Money shot

 

[aussieta]

water that turns green with sudden addition of chlorine is classic iron in the water
as mentioned take a sample of your well water in and have it tested for iron