Last year I contacted you about our pool having a very green tint after it was acid washed by our pool maintenance guy. At this point it is still an aqua color with more green than blue in it, especially with direct sunlight. Originally. Having a white plaster with a medium gray marbled plaster color, the pool was a nice shade of medium blue. Since the acid wash the color has never returned to blue. All chemicals are good.
There are no algae, no excess metals. He also tried an acid "bath", I believe an acid wash after the pool was refilled. The consensus of several local pool builders and service people seems to be that somehow the gray part of the plaster took on a more green/gray color after the acid wash (the first one with pool drained). It is sparkling clean, but just a kind of weird color.
My question is: why would acid washing change the plaster color? Is there any way to restore it to blue without replastering? I have seen a product that gets "painted" on, a type of epoxy I believe. However, we don't want to create a new problem. Would appreciate your thoughts on this. I would also be able to do a phone consultation if you prefer.
Thanks for the follow up Linda
As the original post went, when an acid wash is done on a pool surface a layer of calcium carbonate will be stripped away. This allows the color that is underneath to show. What we're dealing with is a very thin layer of paint, perhaps a few millimeters in thickness. If the plaster is white or grey underneath then that color may start to show through as the blue is stripped away.
Concerning an "acid bath" after the pool was refilled, did the pool guy do an "acid start up"? This is
a common method used to start a pool back up again after replastering. Many times pools with darker plaster will use a bicarbonate start up. This is a relatively new approach. I've only done acid start ups but I've heard some good things about this process. The bicarb doesn't seem to bleach like the acid would. I would start with the company/person who may have done the start up and ask what process was used.
As for getting the original vivid blue color back you would need to drain the pool and start over again. There's no product that I'm aware of that will bring color back to plaster.
Many epoxy paints require a 2 step process and they need to be mixed perfectly and the surface must be prepped or blistering/peeling can occur with a matter of a couple of weeks. What you don't want to do is simply paint over the already existing paint with another kind of paint. Many of these are not compatible and can cause issues down the road. The #1 reason for peeling/blistering paint is a poorly prepped surface.
It's obvious that you have consulted with several pool builders and techs (which is good) in your area and there seems to be a consensus. Being that they are there and possibly have a visual of the pool it would probably be best to take what they have already said. The only overriding factor is the acid wash did (and always will) strip a layer away causing a lighter layer to show through.
I'm never one to turn money down for a consult but I honestly can't think of anything different I would say on the phone that has not been covered in our emails. That being said, here's the link if you choose to do a personal consultation.