Pool Plaster Care / Restoral

[Topper]

My plaster is still in good shape after 5 years but has some darker shades that have appear over the years which I suppose is from a lack of good pool maintenance. Is there a chemical that when added to the water will bleach it back to an even shade again. And, if not what could be done to clear up the blemishes.

Thanks in advance for any advice,

Topper

[waterbear]

My plaster is still in good shape after 5 years but has some darker shades that have appear over the years which I suppose is from a lack of good pool maintenance. Is there a chemical that when added to the water will bleach it back to an even shade again. And, if not what could be done to clear up the blemishes.

Thanks in advance for any advice,

Topper

depends on whether the darker patches are scale deposits, metal stains, organic stains, or just delamination and etching of the plaster.

For scale you would need to acid wash, for metals you would need to use a reducing agent and then a sequestrant, for organic stains you might be able to remove them with chlorine but in bad cases you would need to acid wash.

For actual plaster surface problems you would need to replaster.

Without knowing what your water parameters have been or what the stains actually look like it's really impossible to say any more.

[Topper]

I know the stain starts directly in the path of where I dump the salt and from there they lead down to the pool drain (so I think that salt is the culprit.

[waterbear]

I know the stain starts directly in the path of where I dump the salt and from there they lead down to the pool drain (so I think that salt is the culprit.

what kind of salt are you using? I have seen some of the fine grain "pool salt" cause iron staining because of additives to keep it flowing. Food grade salt will definitely cause iron staining. Solar salt (big crystals) is a safer (and less expensive) choice IMHO. Try holding an ordinary vitamin C tablet on the stained area for about 30 seconds and see if the stain disappears under the tablet. (If the stained area is deep put a handful of vitamin C tablets in a white crew sock and use your pole to hold it on the stained area.) If the stain disappears from just holding vitamin C on it for less than a minute it's iron and we can help you get rid of it. If there is no change then it is probably scale and you will most likely need to acid wash.

Iron stains are tan to brown to orange (they are rust stains), Scale (calcium) stains are off white to tan to brown and often have a rougher feel than the rest of the plaster.

Report back on the results of the vitamin C test. If it fails I will give you another test to try to help identify the stain.