Bright blue to light purple water

[CabanaMan]

This is the third year with our AG 17K gallon pool. Had to drain and refill this year due to pump problems. Installed new pump and filter.

We have a rust problem with our water, although it is not well water. Added Rust and Scale chemicals from pool store and water was sparkling clear blue.

Vacuumed the pool and proceeded to bring chlorine level to shock level with bleach. Next morning, after small rain storm, water turned bright blue to light purple. Numbers from test kit all are in line.

Any thoughts on what this may be or what should I do at this point?

Thanks to all.

[aylad]

I believe that magnesium in the water is generally what causes the purple color, although it's been awhile since anyone here had a problem with it. Do some searching through the forum on Magnesium, and I'll see if I can find the posts from the archives about it....and hopefully in the meantime one of the chemistry experts will stop by and advise you.

Janet

[Water_man]

Here's a quote from this web site: (http://www.arthurspools.com/cyclopedia/poolchem.htm)

Tinted Water and Stains
If minerals are present in the pool water, they can cause the pool water to turn green, brown, yellow, and even purple. The water would look clear but discolored. It can be very difficult to distinguish between green water caused by green algae and green water caused by a mineral problem. A telltale sign of a mineral problem is the discoloring of the pool water shortly after shocking the pool. If this occurs, you will need to add a mineral sequester to the pool. Exactly how much is a guess. We have seen cases where one bottle has solved the problem, and others where multiple bottles were needed. Mineral problems are a tough nut to crack and the pool industry is just now trying to get a handle on it. Stains on the vinyl liner are also treated by adding a mineral sequester. Persistent stains might need to be treated with an "on contact" product that must be applied directly to the stained area of the pool. If the stain is on the bottom of the pool, applying the product directly on the stain can be tricky, but possible.

[waterbear]

I believe that magnesium in the water is generally what causes the purple color, although it's been awhile since anyone here had a problem with it. Do some searching through the forum on Magnesium, and I'll see if I can find the posts from the archives about it....and hopefully in the meantime one of the chemistry experts will stop by and advise you.

Janet
Janet, it's not magnesium (that's a normal part of water hardness along with calcium) buit manganese that colors the water pink to purple!

[waterbear]

Here's a quote from this web site: (http://www.arthurspools.com/cyclopedia/poolchem.htm)
I wonder what website THEY got it from. I have seen this same quote almost word for word on about half a dozen sites.

Tinted Water and Stains
If minerals are present ...


Don't you just love the way they never say metals but use the term "minerals"? It's just so granola-crunchy and wholesoe sounding, isn't it?

[Water_man]

Yeah, you caught that one:D If they suggest a "sequester" they obviously should have said "metals" instead. This is the second recent post, to the best of my knowledge, where people report non-algae related water coloration. I wonder who normally offers water analysis for dissolved metals?

[CabanaMan]

Thanks for the info.

So, at this point, the consensus is to try another metal sequester. I had added Rust/Scale sequester earlier which I thought caused the color problem. But from the article posted, it does seem that multiple bottles may be necessary.

Any recommendations on metal sequester?

[aylad]

Janet, it's not magnesium (that's a normal part of water hardness along with calcium) buit manganese that colors the water pink to purple!

Ah, yes, thanks for catching that!!

Janet