Copper Iron and Manganese Oh My!

[ShallowWater]

The ground water serving my area is known to contain these minerals, some of which are removed for drinking water but trace amounts are considered ok for drinking water but can stain white plaster pools, especially after time passes and they get concentrated due to evaporation and refill.

As we're getting ready to build a pool and we like the classic look of white plaster this is what we've chosen to do on our concrete in ground pool.

I'm looking for suggestions on sequestering these minerals to prevent their build up on the pool surface.

 

[JoyfulNoise]

I suggest you invest in a whole-house water softener and get the plumber to hook it up to your autofill line. Calcium build up is typically going to be worse. It is very unusual to find copper in drinking water and if it is there, then municipalities have to reduce it below EPA actionable limits. That's typically well below what will stain a pool surface. If iron and manganese are indeed high (the EPA doesn't set limits on iron and manganese), then you should also get a greensand type filter to remove iron and manganese.

 

[ShallowWater]

Already have one. When we remodeled the house we repiped with PEX and put in a softener.

It's this one with a sediment filter and carbon filter:

15 GPM will take about 12 hours!

 

[ShallowWater]

California dozen fact regulate iron and manganese but it’s still in the water.. There’s probably trace amounts of copper too but not very much.

Do I still need the green sand filter with the above system? It’s supposed to remove all these via carbon filteration an ion exchange as well as the pre-sediment filter.

If I do need a green sand filter is it on the feed line or part of the pool filtration?

Nevertheless I will get a metal and mineral sample done.

 

[JoyfulNoise]

Go with what you have. No need for an additional greensand unless the water report comes back with high manganese. Iron and manganese irreversible damage ion exchange resins. So over time, exposure to iron and manganese will reduce the efficiency of the softener.

The active carbon really has minimal effect on iron or manganese. It’s main function is to absorb and remove chlorine and chloramines. The presediment filter only removes suspended dirt and silt.

It was not obvious to me from your response but do you have a softened water line or tap outdoors so the pool can have its auto fill hooked up to it? You really want to use softened water for top offs of the pool or else you will fight endlessly with ever-increasing calcium hardness levels. Take it from me, I spent 5 years dealing with hardness before I installed a softener and ran a line to the auto fill. 5 years of banging my head against a wall because after I did the install I couldn’t believe I had waited so long.

 

[ShallowWater]

Go with what you have. No need for an additional greensand unless the water report comes back with high manganese. Iron and manganese irreversible damage ion exchange resins. So over time, exposure to iron and manganese will reduce the efficiency of the softener.

The active carbon really has minimal effect on iron or manganese. It’s main function is to absorb and remove chlorine and chloramines. The presediment filter only removes suspended dirt and silt.

It was not obvious to me from your response but do you have a softened water line or tap outdoors so the pool can have its auto fill hooked up to it? You really want to use softened water for top offs of the pool or else you will fight endlessly with ever-increasing calcium hardness levels. Take it from me, I spent 5 years dealing with hardness before I installed a softener and ran a line to the auto fill. 5 years of banging my head against a wall because after I did the install I couldn’t believe I had waited so long.

The outside water is not currently connected to the softener but the pool fill will be. I remember fighting calcium build up in my prior pool so this sounds like a great idea! I suppose the initial fill should be softened water too so I will get that hooked up for sure.

 

[JoyfulNoise]

The outside water is not currently connected to the softener but the pool fill will be. I remember fighting calcium build up in my prior pool so this sounds like a great idea! I suppose the initial fill should be softened water too so I will get that hooked up for sure.

No. For the initial fill you want to use regular water that has some CH to it or else you’ll damage the plaster surface. Typically you can fill with the regular municipal water and then just maintain the water level using the auto fill attached to the softener.

 

[ShallowWater]

No. For the initial fill you want to use regular water that has some CH to it or else you’ll damage the plaster surface. Typically you can fill with the regular municipal water and then just maintain the water level using the auto fill attached to the softener.

Got it.. I'd probably add calcium chloride anyhow on initial fill but it'd probably be cheaper and less wear on my softener for sure to use straight tap water.

 

[ShallowWater]

FOB is to get a sample of my tap water. Any copper present would most likely come from the newly installed copper end fittings on the PEX line from the main to the backyard.

 

[JoyfulNoise]

Your tap water is probably perfectly fine for filling a newly plastered pool. The common guidance is that the TA and CH should add up to around 500ppm for good plaster quality but, in any case, your plaster applicator will be responsible for start up in order for the warranty to be enforced. So just let them do their thing and then take over when they are done.

Don't bother thinking about calcium chloride. It's not easy find in the western US because we rarely need it out here and it's a waste anyway because the water out here is very hard. If you ever needed to raise CH, and you rarely ever would, you can chlorinate with calcium hypochlorite and use regular unsoftened tap water to autofill with until the CH came up to a desired level. Calcium hardness is a lot less important or critical to deal with, proper sanitation is always the more important aspect of pool care.