New Quartz Plaster-rust colored stains

grivera

Well-known member
Jul 3, 2007
89
Maryland
My new pool was plastered last Thursday, June 28 and filled by Sat, June 30 with city water. The free Chlorine Level is within range according to test strips but the PH is still a couple of shades high. From Wed to Thurs, about four dime sized rust colored stains developed in an isolated area of the pool. They are in the mid point, on the floor, right at the edge. I skimmed the night before and removed as much debris as possible and I've been brushing at least 3 times a day. I haven't used any type of vacum cleaning device under advice of the service department. I've flushed the DE filter twice so far.

Is there anything/what :?: can be done about these stains this early or must the plaster cure longer?
 

JasonLion

TFP Expert
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May 7, 2007
37,879
Silver Spring, MD
There are a couple of things that could be. Someone who knows more about stains should be along soon. In the mean time I suggest you bring the PH down. If it is iron in the water you can keep it under control temporarily by making sure the PH doesn't go up to high. Fresh plaster is going to be raising the PH constantly. There are lots of other possibilities for the stains, but keeping the PH under control is a good idea in any case.
 

JasonLion

TFP Expert
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LifeTime Supporter
May 7, 2007
37,879
Silver Spring, MD
A picture might help. If the stains haven't significantly spread I would suspect that it could be rust from rebar that wasn't covered with enough plaster. If the stains are spreading then there are many other possibilities.
 

mbar

LifeTime Supporter
Apr 24, 2007
257
Ashland PA
You can crush up some vitamin C tablets and put them in a sock and rub them on the stain. If it takes the stain away then it is mineral. Rubbing chlorine on the stain, and the stain lifts then it is organic. If it is metals, you can put in a sequestering agent, follow the directions on the bottle for the size of your pool. It will bring down the ph, which is good for a new plaster pool. Just as Jason says, you need to keep your ph low if there are metals in the water. Post numbers, and let us know how you are doing :)
 

grivera

Well-known member
Jul 3, 2007
89
Maryland
It seems that of the 4 original stains, only 1 is visible now. Using a Swimline 4 in 1 test kit, I get the following results:

PH-7.2
Cl-easily over 3.0 (the chart only goes to 3.0)
 

grivera

Well-known member
Jul 3, 2007
89
Maryland
I put vitamin c tablet in a thin black dree=ss sock and tried to rub it off-no dice. Is this algea for sure? I'll try to take a pic to post.
 

grivera

Well-known member
Jul 3, 2007
89
Maryland
I've added these pics; I hope the attachment works. Some are tan in color, others are darker-maybe brown.javascript:gotoSlideShow('http://www2.snapfish.com/slideshow/AlbumID=167694223/PictureID=3597425245/a=34254545_34254545/t_=34254545')
 

JohnT

Admin
Mod Squad
TFP Expert
Apr 4, 2007
9,607
SW Indiana
I'm a little concerned that you are seeing rebar that wasn't covered deeply enough by the gunite. Algae would brush off, and iron stains from the water would come off with the vitamin C.
 

grivera

Well-known member
Jul 3, 2007
89
Maryland
Could it be? These weren't there initially and then a couple of spots developed that went away within a couple of days. Now these. My SWG was just started up and the service guy said "oh, those are organic, possibly from tese trees around here. I've been really careful not to let anything sit.
 

grivera

Well-known member
Jul 3, 2007
89
Maryland
JohnT, would I have seen the rebar prior to plaster? My project sat for about 6 months between gunite and plaster, never a hint of rebar showing. I was in the empy shell often cleaning debris and such. Also, from watching them do the shotcete, it was applied pretty thick. I certainly hope it isn't that rebar coming through. When I tried the VitaminC test, I had to use my foot as it is in the 4' section. I put the crushed tablets in a thin black sock and rubbed some. I also tried holding a whole tablet between my toes and rubbing, still no dice. I don't know how accurate I was.

Anyone else to comment.
 

cliff_s

Well-known member
Mar 28, 2007
93
I presume by your pool profile that the pool interior finish is Quartz Aggregate. I would guess that
in the Aggregate there are some Iron Pyrite chips. These will rust and give this type of stain.
You cannot permanently remove the stain with acid as the stain will just return. The only way to
remove the stain is to chip the Pyrite out of the finish. If the pool is new the PB should do this.

Here is how to get ride of these types of stains without draining the pool. Get a 10ft. piece of PVC pipe
about 1" will do. Duct tape a sharp cold chisel to one end of the pipe. You can then use this to chip
out the small spot where the Pyrite chip is located. You must remove the Pyrite completely or the
stain will just re-appear.

Iron Pyrite naturally is found within Quartz strata and can be accidentally mixed with Pebble Tec pebbles
or the various Quartz finishes. In fact one neighborhood here had some of the sand used in Stuccoing
the houses contain some Iron Pyrite and they had to(and still do) paint there houses once a year to gety rid of the
rust stains.

Cliff s