What kind of mineral stain is this? with Pictures!

[X-PertPool]

What kind of mineral stain is this? This is only the second time I've seen this in a pool. Acid gets rid of it quick and a sock with cal-hypo will actually darken the stain (see the pictures where I drew the letters O and T) I'm assuming the stains are from the frog system that is being used on the pool.

The link is for the photos
https://plus.google.com/u/0/102527211383561562154/posts/hrtkaaCKVRs

 

[JasonLion]

It is difficult to tell from the pictures. For all I can see it could be copper, iron, or silver. The stains look more gray black to me than anything else, which fits both copper and silver better than it does iron. But I'm having trouble telling if that is the actual color or an artifact of the photos. The Pool Frog contains silver, so I'll guess silver.

When staining is ongoing, cal-hypo used locally will cause staining with any of the metals.

 

[PoolGuyNJ]

If they are purple, they are likely manganese.

Drop the ph and FC. Add sequesterant and a couple CU-Later pouches in the skimmer. Check the fill water.

I don't think its the Frog. It uses silver and copper. Those would leave black and green, depending on the pH. Silver leaves silver oxide (black) with a low pH and copper is copper oxide, green.

Scott

 

[X-PertPool]

The stain's are not purple, they are greyish black (I took some of the photos through my sunglasses to reduce glare).

Customer thought he had black algae when speaking on the phone and I'm pretty sure the pool stores sold him black treat.

What stain removers does everyone like? I know about vitamin c but what about name brand products. I usually use pool stain treat which is a powder (I put it in a sock for spot cleaning). I know i've used some liquid blased removers in the past as well. Just curious if one type is seen as better than the other.

 

[PoolGuyNJ]

Black stains with a Frog will likely be silver oxide.

Ascorbic acid in bulk and cutting out the Frog usually work.

Scott

 

[Swampwoman]

Jacks magic sells a stain identification kit. I haven't purchased it because my stains were clearly iron and my fill source had iron, but I would think the stain test kit might be handy when you're flying blind re what all a customer has put in their pool
That said, silver makes sense -- I've used colloidal silver in the past and that's the color it goes if it "goes bad" (eg oxidizes).

 

[X-PertPool]

Is the ID kit really worth it? I mean it's either mineral or organic right? I have chlorine and acid in the truck. Really don't know whats in the ID kit