Dark Lines in Tub Shell Below The Waterline???

[Richs100]

I was changing my water today in my 2006 HS Envoy, and just below the fountain jets, I see these dark areas and lines under the clearcoat on the shell.  The lines run horizontally, but they are several inches below the waterline.  (And the waterline in my tub has never been that low, even for a short period of time).  They are not on the surface and there is no disruption or defect on the surface of the shell.  

BTW, these lines are only in this area of the tub shell.  There is no sign of them anywhere else around the shell.

Any ideas what this could be?  
Should I get my dealer out to take a look at this?

Hope you can see what I'm talking about in these pics:

[stuart]

It looks to me whats called silver swirl material...Usually it's all over the shell depending on the pull but often it can be on just one side or the other. It is a color mixed in to give the shell a "swirl" look.

HS calls it "Sterling Marble"

[Richs100]

Thanks for the response, Stuart, but the lines I am referring to are the horizontal brown lines, not the verticle marblized veins.  
Maybe the pictures aren't showing it too well.  
Can you see what I am talking about?

[stuart]

Yes, now I see it...They look like mineral or oil stains from where your floating blanket sets in the spa. What have you used to try and clean it?

[Richs100]

I don't think that my waterline or the spa blanket is involved at all.  These lines are 4 to 5 inches below the normal waterline.  I agree that it looks like a waterline discoloration, but I am absolutely sure my waterline has never been at that level.  (I don't think the higher tub jets would work if the water was at that level).  I initally tried to clean the areas with baking soda, but the lines are not on the surface of the tub shell.  It had no effect what so ever.

I am wondering if there might be some kind of a horizontal support on the inside of the shell that might be creating the effect??

I would think that the fact that this is the only area of the tub shell, at that level, that has these marks also tends to negate the idea of classic waterline discoloration.  If it was a mineral or oil stain, wouldn't the lines be all around the tub at that level?  These marks are no where else on the interior of the shell.  Only under the fountain jets.

[Gomboman]

Very strange Rich. Looks like some kind of stain from the picture. I'm assuming it's deep into the finish and will not come off with a magic eraser? When's the last time you inspected the shell? Did you look at it this close during your last water change?

[Richs100]

Hey Gombo

No, I didn't notice it with my last water change about 4 months ago.  But it doesn't jump out at you and it is not visible at all when the tub is full.  So I could have missed it.

It is below the clear coat of the shell, so a magic eraser wouldn't work.  I tried the baking soda which is very good for surface dirt, but this is not on the surface.

Just out of curiosity, when is the next time you will be change your water?  (not that I'm wishing this on you!!)

[Gomboman]

I changed my water about a month ago. I have the Pearl shell and it doesn't show any lines like yours does. It's strange that they are so deep. Are you sure the lines weren't there when the spa was new? I'm sure you would've noticed them.

[hottubdan]

I don't think it will create any structural issue.  However, I have never seen them before.  I would forward the pics to your dealer and get their opinion.  If they don't know and you are concerned, ask them to forward pics to Hot Spring.

[zroger73]

Does your model have a 24-hour circulation pump? It looks to me like there is some componenent of the water that has a specific gravity causing it to hover at the depth you specified. For example, balsa wood has a specific gravity lower than water so it floats. Lead has a specific gravity higher than water so it sinks. It looks like when your water is still, whatever is floating in there is staying in a layer at the depth where your dark ring is.

[Chas]

This tub does have a constant circ pump.

I have seen lines which looked a little like that left on a shell as it was being filled or emptied slowly, but you say it is not on the surface.

At a loss, sorry.


 8-)