Random dark spots in Plaster

[JarCar]

Hey guys, had a question about these random dark spots showing up in my plaster. I've. Priced probably about 6 of them in my pool / hot tub.

I've been having issues with high calcium levels (~500ppm) so wondering if it could be meta stains. Other water Params as of this morning (just had a pool party yesterday):

I also drained about 4inches of water today to see if I can start seeing a decrease in calcium levels.

FC - 6.5
CC - 0
pH - 7.4
TA - 95
CYA - 60
TH - 500

CYA will likely drop after today because of the water change.

Any ideas?

 

[abycat]

Pretty sure it's algae. I think your fc is to low for your cya. Hold on ill check.

- - - Updated - - -

Pretty sure it's algae. I think your fc is to low for your cya. Hold on ill check. Actually 5 fc is the lowest. Have you dipped under 5 lately?

 

[JarCar]

I dipped under 5 yesterday because of a party but they were there before. Wouldn't algae run off when brushed? These will not.

I'll try rubbing them with a chlorine puck.

 

[JarCar]

Chlorine puck didn't work. I tried soaking a sponge full of acid and that seems to be diminishing it a bit.

 

[mknauss]

Chlorine puck didn't work. I tried soaking a sponge full of acid and that seems to be diminishing it a bit.

You can try putting some Vitamin C in a sock and holding against it. Safer than using acid. If it clears, it is a metal stain.

Did a nail or screw or some other stray metal get in the pool?

 

[JarCar]

I'll try the vitamin C. Like the pill form vitamin C?

There was a barrette in the pool but not where these spots are.

 

[mknauss]

Yes, the pills. Take a handful and place in a sock. Mush them up a bit. Hold against the stain for a few minutes. If it clears it, the stain is metal.

Hate to bring it up, but could it be rebar close to the surface of the plaster?

Take care.

 

[JarCar]

Oh man that would be bad. The pool is only about 3 months old.

Ill try the vitamin C, thanks.

Ill also email the plaster manufacturer (NPT) because I believe they do free inspections on new installs.

 

[JarCar]

Just following up on this post. My pool contractor had the manufacturer of the plaster come out to take a look at the stains (now probably 15 - 20). NPT stated (right away) that these are copper stains, however they were caused by poor application of the plaster. Their statement was:

1. When the plaster was mixed, the water mixed with plaster should have been filtered to remove any potential metals (apparently in Houston area copper and manganese are high). Also, when the pool is filled for the first time, a similar hose adapted filter should be used.

2. If the filter is not used, when the pool is started up (in this case an acid hot bath start up) the copper is drawn to the surface of the pool and will randomly show up as darkened green stains. These are not removable as they are in the plaster.

The fix (as recommended by the manufacturer) was to chip out the plaster and redo it Note, the pool was built in March and NPT said the spots could get worse, or I wont see another one, but the existing spots will not go away.

I was so saddened to hear it, but if it gets it fixed :shrug:

Thoughts?

 

[AftonJeeper]

Sorry for your troubles.

If the PB is willing to fix the issue I would let them. Plus it's not like your going to be using the pool much until spring.

Copper stains are difficult to remove, do a search on here and read a few threads.

 

[gnr5]

Just following up on this post. My pool contractor had the manufacturer of the plaster come out to take a look at the stains (now probably 15 - 20). NPT stated (right away) that these are copper stains, however they were caused by poor application of the plaster. Their statement was:

1. When the plaster was mixed, the water mixed with plaster should have been filtered to remove any potential metals (apparently in Houston area copper and manganese are high). Also, when the pool is filled for the first time, a similar hose adapted filter should be used.

2. If the filter is not used, when the pool is started up (in this case an acid hot bath start up) the copper is drawn to the surface of the pool and will randomly show up as darkened green stains. These are not removable as they are in the plaster.

The fix (as recommended by the manufacturer) was to chip out the plaster and redo it Note, the pool was built in March and NPT said the spots could get worse, or I wont see another one, but the existing spots will not go away.

I was so saddened to hear it, but if it gets it fixed

Thoughts?

Im starting to see two dark spots and Im afraid. What happened to your issue???