Well water pool turns green everytime I add chlorine

[tjsdwhit]

Everytime I add chlorine my pool turns green because of the iron and magnese in my well water. After it turns green I add vitimin C and it clears up in 10 minutes but it also takes all the chlorine out of the pool. This is a brutal cycle and the more vitimin C I add the less effective the chlorine. I have asked many pool cleaning services and they do not have a solution except drain the pool and buy cleaner water.

Any thoughts?

[chem geek]

You need a metal sequestrant to keep the metals in solution so that they will not stain nor be colored. The Vitamin C is a reducer so chlorine will oxidize it (i.e. they will use each other up, so to speak) and the lower pH that results from this process and the excess Vitamin C (ascorbic acid) can dissolve colored precipitate.

Just add a metal sequestrant and you should be fine. Vitamin C only needs to be used to remove an existing stain and hopefully with the sequestrant you won't get any stains in the first place.

Richard

[Tjsdwhit]

Richard,
I did what you said and it did not work. It turns out that what I have is magnesium in our water and I am told this is very hard to get out. I used two bottles of metal free, ran my filter for many days and even cleaned my filter twice during this process. This process cleared up my pool but the next time I added chlorine it turned a rust color agin.

Please help!

[chem geek]

I think you mean manganese, not magnesium. Magnesium is in most water (it's the largest contributor to "hardness", more so than calcium) but does not generally precipitate. It's interesting that your pool turns green and not purple since manganese usually looks purple to black. It is usually copper that looks green while iron is usually more rust colored.

By any chance did you ever use either an algaecide or a chlorine source such as Trichlor pucks that contained copper? Do you have details from the water analysis that was done -- including Calcium and Total Hardness and actual copper, iron, manganese concentrations? You need to add an amount of metal sequestrant that is at least as much as the amount of metals that were measured, if not higher. This link also talks about the need for a lot of metal sequestrant.

Assuming you've got manganese and that for some reason it is looking green instead of purple, you could try superchlorinating to precipitate out as much of it as you can (but this could cause staining of plaster surfaces, so it's not a great solution) -- and can either vacuum it from the bottom if it settles when the pump is off or can try a clarifier and filter it out (and then clean the filter). You can also read this link which describes how higher doses of metal sequestrant may be required. Note that using a water filter (ion exchange resin, usually, though one link talks about a micron filter which I doubt would remove metals unless they were already suspended solids) can remove the metals before they get into the pool water. Of course, that can be impractical for the volume of water as found in a pool. Nevertheless, read this link.

I'm guessing that you just didn't use enough metal sequestrant or that perhaps it wasn't as good metal sequestrant as is needed in your case.

I don't have anything else to suggest and hope that others that have successfully battled manganese in well water can help you. Rather than experiment on your entire pool, try filling a large bucket or container with your pool water and do experiments on that first. For example, try using the metal sequestrant in larger amounts (the amounts for the small volume will be tiny, so just use larger "tiny" amounts proportionately). You might need to add some chlorine to the bucket first to get a more intense color.

Richard

[tjsdwhit]

Richard,
You are right it is manganese and now my pool is turning a dark rust like color now. I think the sequestrant got all the other metals out becuase I had our water tested and there wree no other metals except manganese.

Thanks for yor help.

[wapoolguy]

Richard is almost right. Basically how a sequesterant works is by taking the metal and making it bigger so that your filter can pick it up. If your filter has old sand, old cartridge, or is just dirty in general; the metals that were "sequestered" will just pass right through. When you shock the water again it breaks the bond that the sequesterant made and POW your pool is back to square one.

My suggestion is to either chemically clean your filter, or replace it. Then try a product called Metal Magic, by Proteam. Give it some time to work (36-48 hours) and DO NOT SHOCK THE POOL FOR 7 DAYS!! You can also use some type of clarifier, this will help even more with picking up the metals. If you have a Bio-Guard dealer close you should use Sparkle Up, it works great!

Also keep a bottle of Metal Magic on hand for when you add fresh water to the pool you can add some in per the instructions to grab any metals that you just put in.

I hope this helps.