Black Algae?

[tessv]

Hi, all! Quick question... After a long opening process (see my thread in the “opening” section), we finally have folks in the water, and my numbers are holding where they should...

During that process, we noticed a few areas on the walls that seemed to have Black Algae growing... when we tried to do scrape tests, though, nothing came off that we could wipe to check color... also, when we rubbed a puck on it & let it sit then brushed, nothing happened... how else can we determine what it is and confirm it isn’t just patterns in the plaster that we haven’t noticed before?

**during the opening, we had the water tested for metals and all were negative.
My best attempt to photograph it... please note that it’s had that “pattern” since we’ve been open—it isn’t from any of our brushing attempts... extends down the wall about 18-24”

 

[JamesW]

Looks like classic copper staining. Turquoise with black splotches.

 

[tessv]

Looks like classic copper staining. Turquoise with black splotches.

James, should the water have tested positive for copper???

 

[JamesW]

Not necessarily. I suspect that most of the copper has precipitated out in the form of stains and that there is probably very little copper left in the water.

Try allowing a vitamin C tablet sit on a turquoise spot to see what happens.

 

[tessv]

Will do!

 

[JamesW]

Do you have a picture of the whole pool?

 

[tessv]

Do you have a picture of the whole pool?

A quiet pool or with all accessories on?

 

[tessv]

Do you have a picture of the whole pool?

I can get pics of both! My profile pic is an evening image...

 

[tessv]

I can get pics of both! My profile pic is an evening image...

I will say—we do have a feature that we reverently call “the melting pot” or “the cauldron” that is a flaming water feature at the northwest corner of the pool... the feature is an antique double boiler for chocolate from an old Kansas candy factory... works as a fountain, but has a gas line, too, that we light on nights we entertain.... it is a good distance from the pool & has its own filtration system... BUT, it IS a big ol’ copper pot....

 

[tessv]

Daytime shot of melting pot:

 

[tessv]

For scale—taken during the build:

 

[tessv]

Just now, no accessories:

 

[tessv]

Other direction—accessories on:

 

[tessv]

Still pool, evening light, shallow:

Deep:

 

[JamesW]

Is that the original color of the plaster?

If yes, it will camouflage copper stains because they will blend in.

The copper pot should be unrelated.

Has anyone added copper algaecide?

Do you have an ionizer?

 

[tessv]

1. Yes, pretty much! It’s French Grey, so we get quite a bit of color variation depending on sun position, clouds, etc... here’s a google snap of “French Grey” pools, and I would say these accurately reflect our pool color in varying conditions:


2. I texted our PB the same question.... we certainly haven’t, but I don’t know what happened at closing the last two years... will try to find out!!

3. No ionizer, though we have 2 salt cells (Jandy & Pentair)....

 

[JamesW]

Copper is going to be hard to diagnose due to the natural color of the plaster.

Is the Jandy cell a Nature 2 Fusion?

Did the vitamin C tablet have any effect

 

[tessv]

Darn it! No, the Jandy is an Aquapur...

Haven’t run into town to grab vit c tabs yet—all we have are gummies ?... going tomorrow. Thank you so much, @JamesW!!!!!

 

[tessv]

Just tried the Vit C thing... I had a 500mg tab, held it on one of the dark spots ... wasn’t sure what I was looking for—here’s what I observed.

The Vitamin C tab kinda slowly “fizzed” in the water...When I checked underneath where it had contact with the wall, I did not notice any lightening of the dark spot (if it was supposed to work like an eraser?) Rubbing it/scribbling with it yielded no notable effect... Then I just held it and watched until it completely dissolved—thought it looked a little like an ultramarine blue glow to the bottom of the tab, but when I moved it to look at it, it was just white—probably just looking too hard???

What was that test supposed to indicate? What would I have seen if it were definitively a copper stain?

 

[JamesW]

Vitamin C will sometimes make turquoise copper stains darker.

It's difficult to tell what is causing the darker stains.