Brown liner stain

[Phil.c]

Just been away for a week but I shocked the pool before I went, these are the readings today:-

Free Chlor 7.28
Total Chlor 7.28
PH 7.6
Total Alk 19 1
Cal Hardness 89
Cyanide acid Hi

I don't know if this is anything to do with the stain but about two years ago the Water Board worked on a big leak in the village which produced brown water for a short time, however, that winter when the pool was shut down but the pump still running for 2 x four hours per 24 hours, I let the ph get low for a couple of months, totally my fault!

The following year there was a brown stain at the deep end about six feet in diamenter. I bought some Lochlor stain remover followed by No More Metal which completely removed the stain but a week later it was back but this time throughout the whole pool covering all the liner and steps.

I bought some more stain remover and No More Metal but this time it only partially removed the stain, I then phoned the owner of Lochlor in Port Talbot, who suggested that I use Starver and phosphate lowerer which in fairness he supplied, they didn't work.

The electronic water tests I had done at AllSwim showed the pool balance to be right and "NO" metals? I have put a piece of chlorine tablet on the stain just to make sure it wasn't algae etc and it didn't remove anything.

Everyone pointed to the heat exchanger, I took this out and it's like new inside but the brass connectors each side are corroded (pictures attached) I have since, bought and fitted new connectors, the water was shocked three days ago, I did a good backwash yesturday and topped the pool up and tested the water this morning, as expected, everything is high except ph which is normal.

The stain itself is not extremely bad, I mean the blue liner is still visible but with about 40% brown stain over it all.

The water still needs adjusting but I now need to remove the stain.

[Denniswiseman]

Try putting some Ascorbic acid (vitalmin C ) on the stain and see if it disappears
A non permanent solution is to do an Ascorbic Acid Treatment and after put a sequestrant (Lochlor no more metal) into the water
This is not a permanent solution but Teapot has a procedure to remove the iron permanently

[Phil.c]

Thanks for the reply.
The stain is over all the liner so a bit difficult adding vitamin C ?

[Denniswiseman]

The idea is to test a small area
When you do an AA treatment you introduce the AA to the water and it does the whole pool
You can purchase AA on Ebay

[Phil.c]

What does AA actually remove?

Is whatever it removes, caught in the filter or just suspended temporary?

[Denniswiseman]

First of all do the test to see if it works
AA takes the iron out of deposit and puts it into suspension. No More Metal (sequestrant) holds it there. Eventually the sequestrant isn't strong enough to hold it or diluted and you have to add more sequestrant
As I said previously Teapot has developed a method of removing it

[Phil.c]

If AA is the same stuff as Lochlor stain remover, then I've been down that road as I said in my first post, I've tried it three times and with a No more metal follow up, it no longer works.

[Teapot]

https://lochlor.com.au/msds

So many Wonder Magic additives hard to tell exactly what one was used.

AA doesn't remove anything as I explained, it is a reducing agent and puts the oxidised staining metal compound back into a non staining solute non oxidised state where it can be removed.

No more metal is the bullshit name for sequestrant, the metal is still there waiting to be oxidised as soon as the chlorine has broken down the sequestrant and back comes the stain.

[Phil.c]

Understood! But where do I go from here

Any help will be appreciated!

[Phil.c]

Tried vitamin C on a small area, it removed the stain.

[Teapot]

Great, progress. That shows its probably iron and it can be removed.

[Phil.c]

So, where next

BTW. Old filter sand was replaced with new, eight months ago.

[Teapot]

I will email you later as this removal is usually a paid service I offer but with time pressing it's doubtful I could get to you so I will explain it in said email.
I am incredibly dubious of some sand supplies for pools. I changed a customers sand which was new it looked like builders sand, I asked if it said Selco on the bag. Also a case of iron staining.

[Phil.c]

Thanks.

The sand was changed by Best Impressions near Usk, they put my pool in about twenty years ago.

[Teapot]

Sadly Phil, I am so sceptical of people in the industry. Having been in rooms during lecture's and training sessions it became clear that majority haven't a flipping clue!