Stains or Discoloration in Plaster Pool on CLoudy or Overcast Days

I had my very first pool put in, in February. THrilled to death we have been very happy and enjoying it. We had to get a replaster job about 6 weeks after the original plaster job because there was some flaking and othe risses whereby the plaster didnt cure to the gunite very well due to moisture.

In any event, I got a new layer of plaster. Not long after that I began to notice some minor discoloration in the plaster. I talked the pool builder who also says he has a plaster pool and he says even his is like that and thats its normal. Its odd, its only noticeable on cloudy or over cast days, or in the evening when the sun has set. When its sunny or when its night and I have the colored LED lights on, you dont see it.

Has nayone seen these stains or minor discolorations in plaster pools? Im wondering if its some darker color grains of material (I dont even know what all goes into palster) they used in the palster. Thanks in advance.

One way to find out if the stain is from metals or from organics is to get some vitamin C tablets, crush them up and put them in a sock, place the sock on the stain. If the stain disappears, it is from metals. If not, get a chlorine (powder or break up a puck) and do the same, if it disappears, it is from organics. If neither of these work it may be that the plaster cured differently in some spots. That would be something to take up with your builder.

THanks for the tips. Unfortunately, I tried that in some areas. Since this was the second plaster job in two months and he used a new plaster crew because I think the other crew got canned fromt he first debacel we went threw, I trust the builder when he says that is normal. I did the vitamin C trick, chlorine tab and nothing. A steel bristled brush did nothing to these areas.. Fortunately its not overcast too often down here in TX so I dont have to see them. And I got an extra year warranty for the plaster so I know the pool company wasnt screwing around with this.