Seen while draining

[brunoforestier]

I noticed the rings on the attached photo after draining the pool about 40%. I know next to nothing about the construction of my pool, other than it's from the 70s and this is the first time I've drained in in the five years I've owned it.

Anything to be worried about here?

 

[sktn77a]

What kind of pool is it - fiberglass wall, vinyl liner?

 

[RDspaguy]

Looks like a liner.
Are you talking about the light and main drain? I don't see anything else in the pics.

 

[brunoforestier]

It’s painted, I think? I have never been able to completely ascertain the materials used during the pool construction. How can I tell what materials were used?

 

[PoolGate]

Are you talking about those darker blue lines that circle the pool? No clue what those are probably just decorative.

 

[brunoforestier]

The darker blue lines don't appear decorative. To me, it's the same color as when the pool surface is moist. But, it's dry.

To be clear, I am not asking about the light or main drain.

 

[gonfishin]

I believe those rings may be stains from when the pool was last plastered. It's as if the water was filled to a level, stopped for some reason, then resumed to the next level.

 

[PoolGate]

The darker blue lines don't appear decorative. To me, it's the same color as when the pool surface is moist. But, it's dry.

To be clear, I am not asking about the light or main drain.

We really need more information and a closer shot of the lines. Like perhaps it is a vinyl liner and those are seams?

 

[RDspaguy]

I didn't even notice those at first. On closer inspection I think it may be painted concrete. The lines look like form edges from a concrete pour. Like they poured the walls in tiers. Never seen one like that, but that's what it reminds me of.

 

[brunoforestier]

I refilled and drained the pool again in the last week -- I didn't see the rings the second time I drained. Not sure what to make of it.

I did take some different photos, as I'm trying to figure out what my pool is made of. All I can see visibly is tile around the upper edges, and the remainder appears to be painted.